US10291321B2 - Self-identifying one-way authentication method using optical signals - Google Patents
Self-identifying one-way authentication method using optical signals Download PDFInfo
- Publication number
- US10291321B2 US10291321B2 US15/951,446 US201815951446A US10291321B2 US 10291321 B2 US10291321 B2 US 10291321B2 US 201815951446 A US201815951446 A US 201815951446A US 10291321 B2 US10291321 B2 US 10291321B2
- Authority
- US
- United States
- Prior art keywords
- mobile device
- light source
- visible light
- light
- identifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/116—Visible light communication
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q30/00—Commerce
- G06Q30/02—Marketing; Price estimation or determination; Fundraising
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
- H04W12/06—Authentication
-
- H04W4/04—
-
- H04W4/043—
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/30—Services specially adapted for particular environments, situations or purposes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/30—Services specially adapted for particular environments, situations or purposes
- H04W4/33—Services specially adapted for particular environments, situations or purposes for indoor environments, e.g. buildings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/20—Instruments for performing navigational calculations
- G01C21/206—Instruments for performing navigational calculations specially adapted for indoor navigation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
- H04W12/60—Context-dependent security
- H04W12/69—Identity-dependent
- H04W12/77—Graphical identity
Definitions
- U.S. Utility application Ser. No. 13/526,656, entitled “METHOD AND SYSTEM FOR CONFIGURING AN IMAGING DEVICE FOR THE RECEPTION OF DIGITAL PULSE RECOGNITION INFORMATION,” filed Jun. 19, 2012 is a continuation-in-part of and claims benefit under 35 U.S.C. ⁇ 120 to U.S. Utility application Ser. No. 13/446,520, entitled “METHOD AND SYSTEM FOR TRACKING AND ANALYZING DATA OBTAINED USING A LIGHT BASED POSITIONING SYSTEM,” filed Apr. 13, 2012, now U.S. Pat. No. 8,947,513, which is a continuation of and claims benefit under 35 U.S.C. ⁇ 120 to U.S.
- U.S. Utility application Ser. No. 13/526,656, entitled “METHOD AND SYSTEM FOR CONFIGURING AN IMAGING DEVICE FOR THE RECEPTION OF DIGITAL PULSE RECOGNITION INFORMATION,” filed Jun. 19, 2012, now U.S. Pat. No. 8,334,898, is also related to the following applications, filed concurrently with U.S. Utility application Ser. No. 13/526,656, the entire contents of which are incorporated herein by reference: U.S. patent application Ser. No. 13/526,808, filed on Jun. 19, 2012, entitled “METHOD AND SYSTEM FOR MODIFYING A BEACON LIGHT SOURCE FOR USE IN A LIGHT BASED POSITIONING SYSTEM”; U.S. patent application Ser.
- This disclosure relates generally to a system and method for transmitting self-identifying modulated light signals.
- Indoor positioning services refers to methods where networks of devices and algorithms are used to locate mobile devices within buildings. Indoor positioning is regarded as a key component of location-aware mobile computing and is an important element in provided augmented reality (AR) services.
- Location aware computing refers to applications that utilize a user's location to provide content relevant to location. Additionally, AR is a technology that overlays a virtual space onto a real (physical) space. To successfully enable AR and location aware computing, accurate indoor positioning is an important requirement.
- GPS Global Positioning Systems
- RSSI received signal strength indication
- WiFi and Bluetooth wireless access points have also been explored.
- RSSI received signal strength indication
- US Ultrasonic techniques
- US which transmit acoustic waves to microphones, are another method which can be used to approximate indoor position. They operate at lower frequencies than systems based on WiFi and attenuate significantly when passing through walls. This potentially makes US techniques more accurate than WiFi or Bluetooth techniques.
- Optical indoor positioning techniques use optical signals, either visible or infrared, and can be used to accurately locate mobile devices indoors. These are more accurate than the approaches mentioned previously, since optical signals are highly directional and cannot penetrate solid objects. However this directionality limits the potential reliability of optical signals, since difficulty in aligning the receiver and transmitter can occur.
- QR codes Quick Response Codes
- QR codes have the disadvantage of being easily copied.
- anyone having a device with a camera can take a picture of a QR code, print it out, and replicate it.
- QR codes are used in mobile loyalty solutions, it is possible for users to cheat the system by taking pictures of the QR codes and submitting fake scans.
- An alternative emerging technology is Near-Field-Communication (NFC), which uses radio frequency transmission to transmit an authentication message over a short distance.
- NFC Near-Field-Communication
- Many mobile devices do not have NFC capabilities, and NFC terminals have not yet been widely deployed.
- FIG. 1 is a representation of a mobile device receiving light from a LED light source, according to some embodiments of the present disclosure.
- FIG. 2 is a representation of a mobile device receiving multiple sources of light simultaneously from multiple LED light sources, according to some embodiments of the present disclosure.
- FIG. 3 is a representation of the internal components commonly found in a LED light source that is capable of being modulated to send digital data.
- FIG. 4 illustrates information which can be optically transmitted from an LED light source.
- FIG. 5 is a representation of the components which are commonly found in mobile devices which enable them to receive optical signals from LED sources.
- FIG. 6 is a representation of multiple LED light sources sending unique information to multiple mobile devices.
- FIG. 7 illustrates the process of a mobile device sending identification information and receiving location information via a network to a server.
- FIG. 8 illustrates the high level contents of the server which includes databases and web services for individual areas enabled with light positioning systems.
- FIG. 9 illustrates the components inside the databases.
- FIG. 10 illustrates the information contained in the Light IDs database.
- FIG. 11 illustrates the information contained in the Maps database.
- FIG. 12 illustrates the information contained in the Content database.
- FIG. 13 illustrates the information contained in the Analytics database.
- FIG. 14 illustrates the process of a mobile device receiving location and content information via a light-based positioning system.
- FIG. 15 is a process illustrating the background services and how they activate various sensors contained inside the mobile device.
- FIG. 16 illustrates the process of combining multiple information sources with a light-based positioning service.
- FIG. 17 illustrates how a client accesses multiple light positioning enabled locations with multiple mobile devices.
- FIGS. 18A-C are representations of a light source undergoing pulse-width-modulation at varying duty cycles, according to some embodiments of the present disclosure.
- FIGS. 19A-C are representations of a light source undergoing pulse-width-modulation at varying duty cycles with a DC offset, according to some embodiments of the present disclosure.
- FIG. 20 is a block diagram of a DPR modulator with a dimming control system for a light source, according to some embodiments of the present disclosure.
- FIG. 21 is a representation of a block diagram of a DPR modulator, according to some embodiments of the present disclosure.
- FIG. 22 is a block diagram of an encoder for DPR modulation, according to some embodiments of the present disclosure.
- FIG. 23 is a block diagram for a waveform generator for DPR modulation, according to some embodiments of the present disclosure.
- FIG. 24 is a block diagram of a symbol selector system module, which is used to select an appropriate symbol for use in DPR modulation, according to some embodiments of the present disclosure.
- FIG. 25 is a plot of a camera sampling function, according to some embodiments of the present disclosure.
- FIG. 26 is a plot of a modulated illumination function undergoing DPR modulation at a frequency of 300 Hz, according to some embodiments of the present disclosure.
- FIG. 27 is a plot of a convolution of a camera sampling function and a DPR modulated light signal, according to some embodiments of the present disclosure.
- FIG. 28 is a model of the CMOS sampling function for a rolling shutter, according to some embodiments of the present disclosure.
- FIG. 29 is a plot of a sampling function for a CMOS rolling shutter over multiple frames, according to some embodiments of the present disclosure.
- FIG. 30 is a high level flow chart of an algorithm for configuring a mobile device to receive DPR modulated signals, according to some embodiments of the present disclosure.
- FIG. 31 is a high level flow chart of an algorithm for minimizing and locking camera settings using existing mobile device application programming interfaces (APIs), according to some embodiments of the present disclosure.
- APIs application programming interfaces
- FIG. 32 is a high level flow chart of an algorithm for receiving DPR signals on an image sensor, according to some embodiments of the present disclosure.
- FIG. 33 is a high level flow chart of an algorithm for determining tones embedded within a DPR illuminated area, according to some embodiments of the present disclosure.
- FIG. 34 is a high level flow chart of an algorithm for performing background subtraction on images gathered from a DPR illuminated scene, according to some embodiments of the present disclosure.
- FIG. 35 is a high level flow chart of an algorithm for performing motion compensation on video frames when performing DPR demodulation, according to some embodiments of the present disclosure.
- FIG. 36 is a photograph of a surface under illumination from DPR modulated signals, according to some embodiments of the present disclosure.
- FIG. 37 is a post-processed image of a DPR modulated scene after performing background subtraction, according to some embodiments of the present disclosure.
- FIG. 38 is a post-processed image of a DPR modulated scene after row averaging, according to some embodiments of the present disclosure.
- FIG. 39 is a plot of the 1-D spectral content of a DPR modulated surface, according to some embodiments of the present disclosure.
- FIG. 40 is a plot of the 1-D spectral content of a DPR modulated surface after removing DC bias, according to some embodiments of the present disclosure.
- FIG. 41 is a 2-D FFT of a DPR modulated surface, according to some embodiments of the present disclosure.
- FIG. 42 is a 2-D FFT of a DPR modulated surface after applying a low pass filter, according to some embodiments of the present disclosure.
- FIG. 43 is a 2-D FFT of a DPR modulated surface after applying a high pass filter, according to some embodiments of the present disclosure.
- FIG. 44 is a representation of mobile devices receiving multiple sources of light, according to some embodiments of the present disclosure.
- FIGS. 45 and 46 are block diagrams of light sources, according to some embodiments of the present disclosure.
- FIG. 47 is a representation of mobile devices receiving multiple sources of light, according to some embodiments of the present disclosure.
- FIG. 48 illustrates a user interface, according to some embodiments of the present disclosure.
- FIG. 49 illustrates retrieval of a device profile, according to some embodiments of the present disclosure.
- FIG. 50 shows a plot of variance in parameterized phase versus possible modulation frequencies, according to some embodiments of the present disclosure.
- FIGS. 51-53 illustrate filtering of frequency components, according to some embodiments of the present disclosure.
- FIG. 54 illustrates a method for intelligently choosing the appropriate demodulation, according to some embodiments of the present disclosure.
- FIG. 55 illustrates a camera switching algorithm, according to some embodiments of the present disclosure.
- FIG. 56 illustrates a method for resolving between multiple light identifiers, according to some embodiments of the present disclosure.
- FIGS. 57-59 illustrates a mobile device receiving signals from multiple lights simultaneously, according to some embodiments of the present disclosure.
- FIG. 60 is a block diagram of a DPR enclosure module, according to some embodiments of the present disclosure.
- FIG. 61 is a representation of a self-identifying one-way optical transmitter, in accordance with some embodiments.
- FIG. 62 is a representation of a mobile device receiving a self-identifying one-way optical transmission, in accordance with some embodiments.
- FIGS. 63-66 are representations of self-identifying optical transmitters, in accordance with some embodiments.
- FIG. 67 is a representation of a waveform for using pulse width modulation to transmit a signal, in accordance with some embodiments.
- FIG. 68 is a representation of a high-brightness light source broadcasting a modulated signal overhead, in accordance with some embodiments.
- FIG. 69 is a representation of a one-way authentication system being used in a checkout aisle, in accordance with some embodiments.
- the present disclosure relates to a serf-identifying one-way optical transmitter that broadcasts an optical signal via modulation of a light source.
- the transmitter is not necessarily designed for general-purpose illumination. Instead, the transmitter is designed to broadcast a signal that can be successfully received if a mobile device user puts their mobile device in close proximity with the transmitter.
- the user experience for the receiver may be one in which the user “taps” their device onto the transmitter to receive the ID code. Users tapping their devices in this way provides an advantage in terms of security, because users come physically close to the transmitter in order to receive the signal.
- a user's device coming in close proximity to the transmitter also provides an improved user experience, because such an action provides tangible feedback.
- the transmitter can act as a completely stand-alone device.
- the transmitter may be battery powered and preloaded with a specific optical signal.
- the transmitter may be connected to a power and data network if battery replacement is not viable for a particular application or the use of multiple signals is desired.
- a camera-equipped mobile device may utilize its camera to receive the transmitted signal.
- An application on the mobile device may be invoked to initialize the camera and, once invoked, start to acquire images. These images can be captured in succession, in the case of recording video, or can be captured individually.
- the self-identifying one-way optical transmitter may be constantly broadcasting the signal.
- FIG. 1 represents a mobile device 103 receiving light 102 from a LED light source 101 .
- the LED light source 101 may be any lighting source used for general purpose, spot illumination, or backlighting.
- the LED light source may come in several form factors but is not limited to: Edison screw in, tube style, large and small object backlighting, or accent lighting spots and strips.
- any form of LED light is considered as a potential source capable of transmitting information.
- Light 102 is a modulated LED light source 101 , and is part of the visible electromagnetic wireless spectrum.
- LEDs are considered digital devices which may be rapidly switched on and off, to send signals above the rate that the human eye can see. This allows them to be exploited to send digital data through the visible light itself.
- modulating the LEDs turning them on and off rapidly, one may send digital information that is unperceivable to the human eye, but is perceivable by applicable sensors, including but not limited to image sensors and other types of photosensors.
- OOK On Off Keying
- ASK amplitude-shift keying
- the “carrier wave” remains unchanged as this is an inherent property of the light itself.
- the carrier wave corresponding to a blue light signal is uniquely different than the carrier wave corresponding to a red light signal. While these two signals differ only in the wavelength specific to their perceived color, they can be perceived as two discrete signals.
- CMOS complementary metal-oxide-semiconductor
- CCD charge-coupled device
- the image appears to have alternating dark/white stripes.
- the stripes are a direct result of the rolling shutter mechanism, and their width is proportional to the frequency of the pulse width modulated (PWM) signal. Higher frequencies correspond to narrower stripes, and lower frequencies result in wider stripes. Practical frequency ranges for use with this technique are between 60 Hz and 5000 Hz. This technique allows one to exploit the rolling shutter mechanism to recover digital data from an optically encoded signal.
- PWM pulse width modulated
- DPR has the potential for much higher data rates than both OOK and frequency shift keying (FSK).
- FSK and OOK the camera's frame rate limits the data rate.
- the highest possible data rate is half of the frame rate, since each symbol spans over two frames.
- DPR modulation a single frame is sufficient for capturing the transmitted symbol.
- symbols are not “binary”—there are can be as many as 30 different possibilities for a symbol.
- LED light sources In addition to LED light sources, other types of light sources are also capable of transmitting information through modulation. Alternative incandescent and fluorescent technologies can also be exploited to achieve data transmission, however the circuitry is more complex because the turn-on and turn-off times of incandescent and fluorescent lights are subject to additional factors.
- the modulation frequency of the light source is highly dependent on the receiving circuitry. While incandescent and fluorescent technologies generally do not “flicker” on and off during the course of normal operation, LED lighting sources are sometimes designed to flicker above the rate which the eye can see in order to increase their longevity, and consume less power. Most humans cannot see flicker above 60 Hz, but in rare instances can perceive flicker at 100 Hz to 110 Hz. To combat this, lighting manufacturers design flicker above 200 Hz into their lighting products.
- Mobile device 103 may be a smart mobile device and is most commonly found in the form of mobile phones, tablets, and portable laptop computers.
- a mobile device 103 In order for a mobile device 103 to receive information 102 from the LED light source 101 it has an embedded or attached sensor which is used to receive the incoming light 102 signals.
- One such sensor is a camera, which has a typical frame refresh rate between fifteen and sixty frames per second (fps). The fps is directly related to the speed at which optical signals can be transmitted and received by the camera.
- the sensor may capture a number of successive image frames that may later be analyzed to determine if a light source is providing information through light.
- Mobile device 103 may include a processor, module, memory, and sensor in order to capture and analyze light received from light sources.
- the mobile device may analyze the successive image frames captured by the sensor by using the module.
- the module may be logic implemented in any combination of hardware and software. The logic may be stored in memory and run by processor to modify the successive images and analyze the successive images to determine information encoded in the light of one or more light sources.
- the module may be built in to the mobile device to provide the capabilities or it may be downloaded and installed.
- the module may be an application that runs on the mobile device when selected by a user.
- the module may also be used to receive content and other information related to the position of the mobile device and to provide this content to other modules or to the mobile device.
- the reception of optically transmitted information is particularly interesting when used as an indoor positioning system.
- the physical locations of light sources may be used to approximate the relative position of a mobile device 103 within line of sight.
- the mobile device 103 may use information to determine position of the mobile device.
- the mobile device may access a data source containing information about where the lights are physically located to determine position. This data source may be stored locally, or in the case where the mobile device 103 has a network connection, the data source may be stored on an external server 703 .
- the mobile device 103 may optionally download a “map pack” containing the information used to locate itself indoors, instead of relying on an external server 703 .
- the mobile device 103 would first use an alternative existing technique for resolving its position and would use the gained location information to download the appropriate map pack.
- the techniques for receiving geo-location information include, for example, GPS, GSM, WiFi, user input, accelerometer, gyroscope, digital compass, barometer, Bluetooth, and cellular tower identification information. These techniques may also be used to fill gaps between when a position of the mobile device is determined using the light-based technique.
- a mobile device may be placed at times so its camera does not capture light sources. Between these times these alternative existing techniques may be used for filling in position and location information that may be helpful to the user.
- the map pack would contain a map 902 of the indoor space the user is entering, locations of the lights from some sort of existing or third-party lighting plan 1103 , and any location-dependent content 903 for the mobile device 103 to consume. Any requests for location information would simply access data stored locally on the mobile device 103 , and would not need to access a remote server via a network 601 .
- the indoor location reception and calculation may happen with little to no user input.
- the process operates as a background service, and reads from the receiving module without actually writing them to the display screen of the mobile device. This is analogous to the way WiFi positioning operates, signals are read in a background service without requiring user interaction.
- the results of the received information may be displayed in a number of ways, depending on the desired application.
- the user would see an identifying marker overlaid on a map of the indoor space they are moving around in.
- the user might see a mobile media, images, text, videos, or recorded audio, about the objects they are standing in front of.
- FIG. 2 is a representation of a mobile device 103 receiving identification information 102 a - 102 c from multiple LED light sources 101 a - 101 c .
- Each light source is transmitting its own unique piece of information.
- the mobile device 103 may then use the received information to access a database 802 containing information about the relative positions of the LED light sources 101 a - 101 c and any additional content 903 .
- a database 802 containing information about the relative positions of the LED light sources 101 a - 101 c and any additional content 903 .
- relative indoor position may be determined in three dimensions. The position accuracy decreases with less than three sources of light, yet remains constant with three or more sources.
- the mobile device 103 may use photogrammetry to calculate its position, relative to the light sources.
- Photogrammetry is a technique used to determine the geometric properties of objects found in photographic images.
- photogrammetry refers to utilizing the corresponding positions of LED light sources, and their positions in 3-D space, to determine the relative position of a camera equipped mobile device.
- three unique sources of light are seen by the camera on a mobile device, three unique coordinates may be created from the various unique combinations of 101 a - 101 c and their relative positions in space can be determined.
- the following scenario may be considered.
- the sources appear brighter relative to the other pixels on the image.
- Thresholds may then be applied to the image to isolate the light sources. For example, pixel regions above the threshold are set to the highest possible pixel value, and the pixel regions below the threshold are set to the minimum possible pixel value. This allows for additional image processing to be performed on the isolated light sources.
- the end result is a binary image containing white continuous “blobs” where LED light sources are detected, and dark elsewhere where the sources are not detected.
- a blob detection algorithm may then be used to find separate LED light sources.
- a minimum of three separate LED blobs are used to resolve the 3-D position of a mobile device 103 .
- Each LED blob represents a “region of interest” for the information reception, and is simultaneously transmitting a unique piece of information via the modulated visible signal from the light source.
- each region of interest is processed independently of other regions of interest and is considered to be uniquely identifiable.
- a center of mass calculation for each region may be performed to determine the pixel coordinates of the center of each LED light source. This center of mass calculation is performed for each frame to track the regions of interest as they move around the image.
- a detection algorithm captures multiple image frames for each region of interest in order to receive the visible light signal contained in each blob. For each frame in a detected region of interest, a threshold algorithm determines whether the frame contains a “1” (in the case of an aggregate pixel value above the threshold), or a “0” (in the case of an aggregate pixel value lower than the threshold). The threshold algorithm is used since the communication is asynchronous, so the camera receiver period may overlap between the transmission of a “1” and a “0” from the LED light source.
- the result of converting successive image frames in a region of interest to binary values is in essence a down-sampled digital version of the signal received from the LED light source.
- demodulation of the down-sampled digital signal is used to recover the transmitted bits. This down sampling is used due to the fact that the signal modulation frequency should be above the rate at which the human eye can see, and the image sensor frame rate is typically limited to 15-30 fps.
- the mobile device 103 processes data on a frame-by-frame basis. Each frame is split into separate regions of interest, based on the detection of light sources. For each region of interest, a thresholding algorithm is used to determine whether a given region is “on” or “off”. This is done by taking the average pixel value for the region and comparing it to the threshold value. If the region is “on”, the demodulator assumes the light source has just transmitted a “1”. If the region is “off”, the demodulator assumes the light source has sent a “0”. The result of this is the equivalent of a 1-bit analog-to-digital conversion (ADC), at a sampling rate which is equal to the frame rate of the camera.
- ADC analog-to-digital conversion
- the results of the ADC conversation are stored in a circular buffer.
- a sliding correlator is applied to the buffer to look for the presence of start bits 402 . If start bits 402 are found, the demodulation algorithm assumes it is reading a valid packet of information 401 and proceeds to capture the rest of the transmission. Two samples are used for each bit, so the algorithm creates a linear buffer that is twice the size of the remaining packet. Each subsequent ADC is written sequentially to the linear buffer. When the linear buffer is filled, the demodulation algorithm performs a Fast Fourier Transform (FFT) on the buffer to recover the transmitted signal.
- FFT Fast Fourier Transform
- FIG. 3 describes internal components commonly found in LED light source 101 with the addition components to allow for the transmission of optical signals.
- the LED light source 101 typically contains an alternating current (AC) electrical connection 301 where it connects to an external power source, an alternating current to direct current (AC/DC) converter 302 which converts the AC signal from the power source into an appropriate DC signal, a modulator 304 which interrupts power to the LEDs in order to turn them on and off, a microcontroller 305 which controls the rate at which the LEDs are modulated, and a LED driver circuit 303 which provides the appropriate amount of voltage and current to the LEDs.
- AC alternating current
- AC/DC alternating current to direct current
- Electrical connection 301 is an electrical source that is used to supply power to the LED light source 101 . This most commonly comes in the form of a 120 Volt 60 Hz signal in the United States, and 230 Volt 50 Hz in Europe. While depicted in FIG. 3 as a three pronged outlet, it may also take the form of a two terminal Edison socket which the bulb is screwed into, or a bundle of wires containing a live, neutral, and/or ground. When considering other forms of lighting such as backlighting and accent lighting, the electrical connection may also come in the form of a DC source instead of an AC source.
- LED light sources contain an AC/DC converter 302 that converts the alternating current from the power source 301 to a direct current source used internally by the components found inside the bulb or light source.
- the converter takes the alternating current source commonly found in existing lighting wiring and converts it to a direct current source.
- LED light sources generally use direct current, therefore an AC/DC converter is found in most lighting products regardless of form factor.
- LED driver 303 provides the correct amount of current and voltage to the LEDs contained inside the lighting source. This component is commonly available and may have either a constant-current or constant-voltage output.
- the LEDs found inside most lighting sources are current-controlled devices, which require a specific amount of current in order to operate as designed. This is important for commercial lighting products because LEDs change color and luminosity in regards to different currents.
- the LED driver circuitry is designed to emit a constant amount of current while varying the voltage to appropriately compensate for the voltage drops across each LED.
- there are some high voltage LEDs which require a constant voltage to maintain their color and luminosity. For these cases the LED driver circuitry provides a constant voltage while varying the current.
- Modulator 304 serves the function of modulating the LED light source 101 on and off to optically send light 102 signals.
- the circuits featuring the modulator may simply consist essentially of solid-state transistors controlled by a digital input.
- the modulator 304 turns the LEDs on and off by allowing or preventing current flow. When current flows through the modulator with the switches closed the LEDs turn on, and when the switches are open in the modulator no current can flow and the LEDs turn off.
- the modulator is controlled by an additional logic component, it has the ability to send repeating patterns of on/off signals in order to transmit digital data through the visible light 102 .
- the modulator interfaces directly in between the AC/DC converter 302 and the LED driver 303 , and is controlled by a microcontroller 305 .
- the microcontroller 305 provides the digital input signal to the modulator unit 304 . This function may also be achieved using a field-programmable gate array (FPGA), but typically consumes more power with added complexity.
- the microcontroller's 305 task is to send a pre-determined sequence of signals to the modulator 304 which then interfaces with the LED driver 303 to modulate the outgoing visible light from the LED source 101 .
- the microcontroller contains a nonvolatile memory storage area, which stores the identification code of the light signal. Examples of possible nonvolatile memory sources include programmable read only memory (PROM), electrically erasable programmable read only memory (EEPROM), or Flash.
- the microcontroller 305 contains a digital output pin, which is used to modulate the light output. To generate the output signal waveforms, timer modules within the microcontroller 305 are used. Typical logic levels for the digital output are 3.3V and 5V. This digital output feeds into the modulator 304 which interrupts the driver circuit 303 for the LED light source 101 . Alternatively, if the LED light source requires lower power, such as backlighting or individual LED diodes, the output of the microcontroller 305 could also be used to drive the light sources directly.
- the sequence of signals sent from the microcontroller 305 determines the information that is transmitted from the LED light source 101 .
- FIG. 4 describes the information 401 format of the optically transmitted information from the light 102 .
- each packet of information contains some sort of starting bit sequence, which indicates the beginning of a packet, followed by data 403 , and some sort of error detection identifier.
- the size and position of each portion of information is dependent on the application and is also constrained by requirements of the receiving device.
- Each packet of information 401 transmitted from the LED light source 101 contains a sequence of starting bits 402 , followed by data 403 , and then terminated with an error detection code 404 . Since the LED light sources 101 are continually broadcasting information 401 , erroneous packets are simply discarded while the receiver listens for the starting bits 402 , indicating the beginning of the next packet. In cases where multiple sources of light are observed by a mobile device 103 , multiple pieces of information 401 are received simultaneously.
- Information 401 describes the encoded information that is transmitted by the LED light source 101 .
- the information 401 is contained in a packet structure with multiple bits which correspond to numeric integer values.
- the data 403 portion of the information packet may include unique ID codes 701 .
- the ID code may include location information in the ID code that provides a general indication of geographical location of the light. This geographical location information may be used to more quickly locate light source information that is used in determining indoor positioning on the mobile device. For example, the geographical information may point to a database to begin searching to find relevant information for positioning.
- the geographical information may include existing location identifiers such as area code, zip code, census tract, or any other customized information.
- the ID code 701 is static and is assigned during the calibration phase of the LED light source 101 during the manufacturing process.
- One method to assign the ID code 701 is to place instructions to generate a random code in the nonvolatile memory. Once the LED light source 101 is powered on the microcontroller reads the ID code 701 from the nonvolatile memory storage area, and then uses this code for broadcasting each and every time it is subsequently powered on. Since the ID code 701 is static, once it is assigned it will be forever associated locally to the specific LED light source 101 which contains the microcontroller 305 .
- FIG. 5 describes the components found in mobile devices 103 that are capable of receiving optical information.
- the mobile device contains an image sensor 501 to capture optically transmitted information, a central processing unit 502 to decipher and manage received information, and a network adapter 503 to send and receive information.
- Photosensors are devices which receive incoming electromagnetic signals, such as light 102 , and convert them to electrical signals.
- image sensors are arrays of photosensors that convert optical images into electronic signals. The ability to receive signals from multiple sources is an important benefit when using image sensors for receiving multiple optical signals.
- Image sensor 501 is a typical sensor which is found in most smart devices. The image sensor converts the incoming optical signal into an electronic signal. Many devices contain complementary metal-oxide-semiconductor (CMOS) image sensors; however, some still use charge-coupled devices (CCD). CMOS image sensors are the more popular choice for mobile devices due to lower manufacturing costs and lower power consumption. There are several tradeoffs to consider when choosing an image sensor to perform photogrammetry on multiple LED light sources 101 . One tradeoff is between the camera resolution and the accuracy of the photogrammetric process when triangulating between multiple light sources—increasing the number of pixels will increase the accuracy. There is also another tradeoff between the data rate of the transmission and the sampling rate (in frames per second) of the camera.
- CMOS complementary metal-oxide-semiconductor
- the data rate (in bits/second) is half the frame rate of the camera (e.g., a 30 fps camera will receive 15 bps). And finally when determining the length of the information 401 packet, the larger the size the longer the reception period, as more bits generally requires longer sampling periods to capture the full message.
- CPU 502 is typically a generic CPU block found in most smart devices.
- the CPU 502 is in charge of processing received information and sending relevant information to the network adapter 503 . Additionally the CPU has the ability to read and write information to embedded storage 504 within the mobile device 103 .
- the CPU 502 may use any standard computer architecture. Common architectures for microcontroller devices include ARM and x86.
- the network adapter 503 is the networking interface that allows the mobile device 103 to connect to cellular and WiFi networks.
- the network connection is used in order for the mobile device 103 to access a data source containing light ID codes 701 with their corresponding location data 702 . This may be accomplished without a data connection by storing location data 702 locally to the mobile device's 103 internal storage 504 , but the presence of a network adapter 503 allows for greater flexibility and decreases the resources needed.
- the network adapter 503 is also used to deliver location dependent content to the mobile device when it is connected to a larger network 601 .
- FIG. 6 is a representation of multiple LED sources sending light 102 a - d containing identification information 102 to multiple mobile devices 103 a - 103 b .
- the light sources are acting as non-networked broadcast beacons; there are no networking modules or physical data wires connecting them. This property is desirable when looking towards a commercial installation of numerous LED light sources 103 a - 103 b , as additional wiring and networking will not be required.
- the mobile devices have the ability to send and receive additional information from a local source or a network 601 . Once the mobile device 103 receives identification information 401 from the light sources, it then asks a local or remote source for additional information.
- Enclosed area 602 is a spatial representation of an enclosed room containing four LED sources 101 a - 101 d and two mobile devices 103 a - 103 b , meaning that they may operate next to each other without interference.
- the received image feed from the mobile device sees one or more distinct bright sources of light, it has the ability to differentiate and receive the unique information without interference. Because the light capture is based on line of sight, interference is mitigated. In this line of sight environment, interference may arise when the light capture mechanism of the mobile device is blocked from the line of sight view of the light source.
- Network 601 represents a data network that may be accessed by mobile devices 103 a - 103 b via their embedded network adapters 503 .
- the network may consist of a wired or wireless local area network (LAN), with a method to access a larger wide area network (WAN), or a cellular data network (Edge, 3G, 4G, LTS, etc).
- LAN local area network
- WAN wide area network
- Edge 3G, 4G, LTS, etc.
- the network connection provides the ability for the mobile devices 103 a - 103 b to send and receive information from additional sources, whether locally or remotely.
- FIG. 7 describes how the mobile device 103 receives location data 702 .
- the mobile device 103 sends decoded ID codes 701 through a network 601 to a server 703 , which sends back location information 702 .
- the decoded ID codes 701 are found in the information 401 , which is contained in the optically transmitted signal.
- the mobile device 103 After receiving this signal containing a unique ID code 701 the mobile device 103 sends a request for location data 702 to the server 703 , which sends back the appropriate responses.
- the request could include other sensor data such as but not limited to GPS coordinates and accelerometer/gyroscope data, for choosing between different types of location data 702 and any additional information.
- Location data 702 is the indoor location information which matches the received information 401 .
- the location data 702 corresponds to indoor coordinates which match the ID code 701 , similar to how outdoor GPS tags known locations of interest with corresponding information.
- the location data 702 could also contain generic data associated with the light identification information 401 . This could include multimedia content, examples of which include recorded audio, videos, and images.
- the location data 702 may also vary depending, for example, on other criteria such as temporal criteria, historical criteria, or user-specified criteria.
- the temporal criteria may include the time of day.
- the historical criteria may include user location history (e.g., locations visited frequently), Internet browsing history, retail purchases, or any other recorded information about a mobile device user.
- the user-specified criteria may include policies or rules setup by a user to specify the type of content they wish to receive or actions the mobile device should take based on location information.
- the user-specified criteria may include how the mobile device behaves when the user is close to an item that is on sale.
- the user may specify that a coupon is presented to the user, or information about the item is presented on the mobile device.
- the information about the item may include videos, pictures, text, audio, and/or a combination of these that describe or relate to the item.
- the item may be something that is for sale, a display, a museum piece, or any other physical object.
- Server 703 handles incoming ID codes 701 , and appropriately returns indoor location data 702 to the mobile devices 103 .
- the handling may include receiving incoming ID codes, searching databases to determine matches, calculating position coordinates based on the ID codes, and communicating indoor location data 702 . Since the LED light sources 101 are acting as “dumb” one-way communication beacons, it is up to other devices to determine how to use the ID codes to calculate position information and deliver related content.
- the server 703 may include the information used to link ID codes 701 to physical spaces and to deliver location-specific content.
- the server is designed to handle the incoming requests in a scalable manner, and return results to the mobile devices in real-time.
- the server may include one or more interfaces to the network that are configured to send and receive messages and information in a number of protocols such as Internet Protocol (IP) and Transmission Control Protocol (TCP).
- IP Internet Protocol
- TCP Transmission Control Protocol
- the protocols may be arranged in a stack that is used to communicate over network 601 to mobile device 103 .
- the server may also include memory that is configured to store databases and information used in providing position coordinates and related location based content.
- the server may include one or more modules that may be implemented in software or other logic. These modules may perform calculations and perform operations to implement functionality on the server.
- the server may use one or more processors to run the modules to perform logical operations.
- FIG. 8 delves into location-specific areas 801 containing databases 802 and web services 803 .
- the areas 801 represent a subset of databases 802 and web services 803 for individual locations where there are installed LED light sources 101 .
- the server 703 directly communicates with these installations, which have their own separate sets of information.
- databases 802 represent the stored information pertaining to a specific area 801
- the web services 803 represent services which allow users, customers, administrators, and developers access to the ID codes, indoor locations, and other information.
- the server 703 In order to send relevant information, after each received ID code 701 , the server 703 requests information pertaining to the specific area 801 . Contained in each area 801 , are databases which contain information corresponding to the specific ID code 701 . This information can take multiple formats, and has the ability to be content specific to a variety of static and dynamic parameters.
- the server 703 may constrain its search space by using existing positioning technologies available to the mobile device 103 or from information in the light source ID code depending on the embodiment. In essence the server looks for the light IDs 901 within a specific radius of the current approximate position of the mobile device 103 , and ignores those that are geographically irrelevant. This practice is known as “geo-fencing”, and dramatically reduces the request/response time of the server 703 . As final verification, if the database 802 contains one or more of the same IDs within the current search space that match the ID codes received by the mobile device 103 within a specific time frame, then a successful transaction can be assumed.
- each database 802 contains numerous sub-categories which store specific types of information.
- the categories are labeled light IDs 901 , maps 902 , content 903 , and analytics 904 .
- Light IDs 901 is a category which contains records of the individual light ID codes 701 which are contained in an area 801 . In a typical light positioning enabled installation, there will be tens to hundreds of unique LED light sources 101 broadcasting unique ID codes 701 .
- the purpose of the light IDs 901 database is to maintain and keep a record of where the ID codes 701 are physically located in the area 801 .
- These records may come in the form of but are not limited to GPS (latitude, longitude, and altitude) coordinates that are directly mapped into an indoor space. For instance, most indoor facilities have information about the number of installed lights, how far apart they are spaced, and how high the ceilings are. This information may be matched with building floor plans or satellite imagery to create a digital mapping of where each light is positioned.
- location-specific maps 902 may take on many physical and digital forms, either directly from the management of the location, or a third-party vendor or outside source.
- location-specific content 903 and analytics 904 are also contained inside the databases 802 .
- FIG. 10 is a description of the ID log 1001 information contained in the Light IDs database 901 . It is a representation of the file structure that contains individual records corresponding to individual light ID codes 701 found within different areas 801 . In a typical area 801 there is a possibility of having duplicate ID codes 701 since there are a finite number of available codes. The size of the ID code 701 is proportional to the length of the data 403 field contained in the optical information 401 .
- additional distinguishing information may be contained inside of the individual log records; ID 1 1001 , ID 2 1003 , and ID 3 1004 .
- This information may contain additional records about neighboring ID codes 701 that are in physical proximity of the LED light source 101 , or additional sensor data including but not limited to: accelerometer or gyroscope data, WiFi triangulation or fingerprinting data, GSM signature data, infrared or Bluetooth data, and ultrasonic audio data.
- Each additional sensor is an input into a Bayesian model that maintains an estimation of the current smartphone position and the uncertainty associated with the current estimation. Bayesian inference is a statistical method used to calculate degrees of probability due to changes in sensory input. In general, greater numbers of sensory inputs correlate with lower uncertainty.
- a user equipped with a specific mobile application will need to walk around the specific area 801 .
- the mobile application contains map 902 information of the indoor space, with the positions of the LED light sources 101 overlaid on the map.
- ID codes 701 from the lights.
- the mobile application sends a request to the server 703 to update the light location contained in the lighting plan 1103 with the ID code 701 .
- Additional user-provided 1104 metadata including but not limited to current WiFi access points, RSSI, and cellular tower information may also be included with the server request to update additional databases.
- calibration of LED light source 101 locations may also be achieved via crowd-sourcing.
- mobile application users move around an indoor space receiving ID codes 701 , they will send requests to the server 703 containing the light ID code 701 received, the current approximate position (based on other positioning techniques such as WiFi, GPS, GSM, and inertial sensors) and the error of the current approximation.
- machine learning algorithms on the server 703 may be used to infer the relative position of each LED light source 101 . The accuracy of this calibration method depends heavily on the number of mobile application users.
- FIG. 11 is a description of the maps database 902 and map log 1101 information containing floor plans 1102 , lighting plans 1103 , user-provided information 1104 , and aggregated data 1105 .
- Map log 1101 is a representation of the file structure that contains the information found inside the maps database 902 .
- Information may come in the form of but is not limited to computer-aided drafting files, user-provided computerized or hand drawn images, or portable document formats.
- the information residing in the maps database 902 may be used both to calibrate systems of multiple LED light sources 101 , and to augment the location data 702 that is sent to mobile devices 103 .
- Floor plan 1102 contains information about the floor plan for specific areas 801 .
- the contained information may be in the form of computer-aided drafting files, scanned images, and legacy documents pertaining to old floor plans.
- the information is used to build a model corresponding to the most recent building structure and layout.
- These models are subject to changes and updates through methods including but not limited to crowd sourcing models where users update inaccuracies, third-party mapping software updates, and additional input from private vendors.
- Lighting plan 1103 contains information about the physical lighting fixture layout, electrical wiring, and any additional information regarding the lighting systems in the area 801 . This information may also come in a variety of physical and digital forms such as the floor plan 1102 information.
- the lighting plan 1103 information is used in the calibration process of assigning light ID codes 701 to physical coordinates within an area 801 . In essence, a location with multiple LED light sources 101 acts as a large mesh network except, in this case, each node (light ID 701 ) is a non-networked beacon of information that does not know about its surrounding neighbors. To help make sense of multiple light ID codes 701 , the lighting plan 1103 information is used as one of many ways to tell the backend server 703 where LED light sources 101 are located.
- User-provided information 1104 contains additional data that the user manually uploads in regards to building changes, updates, or new information that is acquired.
- the user in this case is most likely the facility manager or staff member, but such information may also originate from an end user of the system who contributes via a crowd sourcing or machine learning mechanism. For instance, if an end user was using a light-based positioning system in a museum and was unable to find a particular exhibit or noticed inaccurate information in regards to location or classification of the exhibit, they could red flag the occurrence using their mobile device 103 .
- this user-provided information 1104 may be used to update and repair inaccuracies in the maps 902 database.
- Aggregated data 1105 contains information that is gathered by the system that may be used to augment the current information that is known about the mapping environment. This may occur during normal operation of the system where multiple mobile devices 103 are constantly sending and receiving location data 702 from the server 703 . Over time the aggregation of this data may be used to better approximate how light ID codes 701 correspond to the physical locations of the LED light sources 101 . For instance, if multiple mobile devices 103 consistently receive a new ID code 701 , in a repeatable pattern with respect to additional known ID codes 701 and other sources of location information, then this information may be recorded and stored in the aggregated data 1105 database. This information may additionally be used to recalibrate and in essence “self-heal” a light-based positioning system.
- FIG. 12 is a description of the content database 903 and content log 1201 information containing static content 1202 , user-based content 1203 , and dynamic content 1204 .
- Content log 1201 is a representation of the file structure that contains the information found inside the content database 903 .
- Static content 1202 refers to unchanging information that is associated with the specific area 801 . This may refer to the previous example in which a facility manger loads specific content into the content 903 database before a user enters the specific area 801 . This type of information may take the form of but is not limited to audio recordings, streaming or stored video files, images, or links to local or remote websites.
- User-based content 1203 refers to content that is dependent on user criteria.
- the content may depend on, but is not limited to, user age, sex, preference, habits, etc. For instance, a male user might receive different advertisements and promotions than a female would. Additionally, age and past purchase habits could also be used to distinguish which is the correct piece of content to be presented to the user.
- Dynamic content 1204 refers to content which changes with varying frequency.
- the content may change dependent on a temporal bases, daily, weekly, monthly, etc. For instance, seasonal marketing and content could be automatically presented to the user dependent on the month of the year, or content in the form of morning, evening, or nightly specials could be presented numerous times throughout the individual day.
- point of purchase 1205 information may be delivered as well. This could be implemented by using the received ID code 701 to a secure connection that establishes and completes a transaction linked to a user's selected payment method. Additionally, a standalone point of purchase feature could be implemented by simply linking ID codes 701 directly to merchandise or services.
- FIG. 13 is a description of the analytics database 904 and analytics log 1301 information containing frequency 1302 , dwell time 1303 , path taken 1304 , and miscellaneous 1305 .
- Analytics log 1101 is the file structure that contains the information found inside the analytics database 904 .
- Frequency 1302 refers to the number of times each end user visits a particular location inside of a specific area 801 . Separate records are maintained for individual users, and the frequency is aggregated and sorted in the frequency files database 904 .
- Dwell time 1303 refers to the time spent in each particular location inside a specific area 801 . Separate records are maintained for individual users, and the dwell times are aggregated and sorted in the dwell time file. Path taken 1304 refers to the physical path taken by a user in each specific area 801 .
- the store owner Prior to the customer entering the store, the store owner has already calibrated and preloaded the database 802 with the unique LED light sources 101 , map 902 information pertaining to the store floor plan 1102 , user-provided 1104 product locations, and content 903 in the form of multimedia and local deals in the form of promotions that may only be activated by visiting that particular section of the store.
- the customer is walking around the store looking to find particular items on her shopping list that she has already digitally loaded onto her mobile device 103 .
- the customer is prompted by her mobile device 103 that one of the items on her list has changed locations and an image of the store layout is displayed with a flashing icon indicating where her desired product has moved.
- the mobile phone may guide her to the new product.
- an informational video is prompted on her screen detailing the most popular recipe incorporating that product and how it is prepared.
- the customer receives a discount promotion for taking the time to seek out the new location of the product.
- the store owner now gains value from learning about the shopping experiences of the customer. This comes in the form of aggregated data that is captured and stored in the analytics 904 section of his store's database 802 .
- This example is one of many applications that may be enabled with an accurate indoor light-based positioning system.
- FIG. 14 is a process describing the act of receiving location and content information through visible light.
- User places mobile device under light 1401 corresponds to the act of physically placing a camera equipped mobile device 103 underneath an enabled LED light source 101 .
- the user stands approximately underneath or adjacent the LED light source 101 , and the mobile device has the LED light source 101 in view of the camera lens.
- sample image sensor 1402 refers to the act of turning on and reading data from the embedded image sensor in the mobile device 103 .
- Receive ID? 1403 is a decision block which either moves forward if a location ID is received, or returns to sample the image sensor 1402 .
- Get location data corresponding to ID from server 1404 occurs once a location ID has been received.
- the mobile device queries the server asking for location data 702 relevant to the ID code. This describes the process of a user obtaining an ID code 701 from a non-networked LED light source 101 , and using the unique identifier to look up additional information from either the server 703 or a locally stored source.
- Content? 1405 is another decision block which determines if there is location-based content associated with the received ID code. If content is available the process continues on to the last block 1406 where the content is queried; if not, the process ends.
- the get content data corresponding to ID from server 1405 refers to the act of retrieving content data associated with a known location from either a server 703 or local source.
- FIG. 15 is a process describing the act of turning on the application background services and determining when to sample the image sensor.
- Initiate background service 1 1501 is the primary background running service on the mobile device. This service is tasked with initiating a function that can communicate wirelessly to determine if the mobile device is close to an enabled area.
- the wireless communication includes radio frequency communication techniques such as global position system (GPS), cellular communication (e.g., LTE, CDMA, UMTS, GSM), or WiFi communications.
- GPS global position system
- cellular communication e.g., LTE, CDMA, UMTS, GSM
- WiFi communications e.g., WiFi communications.
- Determine position 1502 is the function that periodically samples the wireless communication signal and based on distance parameters decides whether or not the mobile device is close enough to an area to move forward to the next service.
- Light positioning enabled? 1503 is a decision block that moves forward if the mobile device is close to an enabled location, or repeats the previous function if not.
- Initiate background service 2 1504 is activated once the mobile device enters an enabled area. The service is tasked with initiating the functions that receive location information via the modulated light.
- Sample ambient light sensor 1505 is the first function of the previous service that samples the ambient light sensor data as soon as the sensor detects a change. The function of this task is to determine if the sensor has gone from dark to light, if the user takes the device out of a pocket or enclosure, or from light to dark, the user has placed the device inside of a pocket or enclosure. As an alternative to sampling the light sensor, the algorithm could also look for a change in the accelerometer reading. This may correspond to the user taking the phone out of their pocket. Detect change? 1506 is the decision block that moves forward if the ambient light sensor has gone from dark to light, meaning that the mobile device is potentially in view of surrounding modulated light.
- FIG. 16 is a process describing the act of determining a mobile device's position using a variety of information sources.
- Sample GPS/GSM 1601 refers to the act of determining if the mobile device is close to an enabled area.
- Enabled area? 1602 is a decision block which moves forward if the mobile device is close to a enabled area, or returns to the previous block if not.
- Sample alternative sources 1603 refers to the act of leveraging existing alternative positioning technologies such as WiFi, Bluetooth, ultrasound, inertial navigation, or employing an existing service using one or more of any available services.
- Record internal sensor data 1606 is a task which records the current accelerometer data for a period of time before returning to the Sample image sensor 1402 block. This task is performed so that location information is constantly being collected even when modulated light is not being detected. This allows the mobile device and/or server to keep track of the mobile device's position.
- FIG. 17 is a system diagram describing how a client device 1704 interacts with a light-based positioning system 1709 .
- Network 601 is a generic local or remote network used to connect mobile devices 103 contained in locations A 1701 , B 1702 , and C 1703 with the light-based positioning service 1709 .
- Each location contains multiple LED light sources 101 , each of which broadcast unique identification codes 701 .
- a mobile device may use the database service application 1710 which contains multiple privilege levels for different levels of access.
- the client privilege level determines read/write permissions to each of these databases.
- These levels include users 1705 which refer to general front end system users, administrators 1706 which are usually IT or operations management level within an installation, developers 1707 which have access to the application programming interfaces of the system for use in custom application development, and root 1708 level which contains master control over the users and access to everything contained in the system and databases.
- Mobile devices in each location 1701 , 1702 , and 1703 receive identification codes 701 from lights in their respective locations. They then send the received identification codes 701 through the network 601 which connects to database service application 1710 , through user application 1705 , and has read access to maps 902 and content, and write access to analytics 904 .
- a generic client, 1704 connects to database service application 1710 through network connection 601 .
- the client uses a password authorized login screen to access the respective permission status.
- Clients with administrator permissions have read/write access to light IDs 901 , read access to maps 902 , read/write access to content 903 , and read access to analytics 904 .
- Clients with developer permissions 1707 have read access to light IDs, read access to maps 902 , read/write access to content 903 , and read access to analytics 904 .
- a client with root permissions 1708 has read/write access to databases 901 - 904 .
- FIG. 17 describes the top-down approach to an exemplary implementation of a light-based positioning system.
- known locations of installed non-network standalone LED light sources 101 are used to accurately identify the relative position of mobile devices 103 .
- the background processes running on the mobile device 103 have been described in FIGS. 14, 15, and 16 .
- the mobile device uses this information to query a database 802 for additional information.
- This information may come in many forms, and is used to create a more personalized experience for the user. As initially mentioned, this local experience is used for location-aware mobile computing, and augmented reality applications.
- location-based analytics applications may be enabled from the aggregated data and traffic running through the server 703 .
- the use of light-based positioning capabilities provide a number of benefits.
- the positioning information obtained by using light sources is highly precise compared to alternative techniques for positioning information.
- the accuracy of a light-based positioning system may be down to a few centimeters in three dimensions in some embodiments.
- This positioning ability enables a number of useful services to be provided.
- additional mobile device information may be used in combination with the positioning information.
- accelerometer position information may be used in conjunction with light source based position to offer augmented reality or location aware content that relevant to the device's position.
- the relevant content may be displayed to augment what is being displayed on the mobile device or the display can provide relevant information.
- Applications on the mobile device may also be launched when the mobile device enters certain areas or based on a combination of criteria and position information. The applications may be used to provide additional information to the user of the mobile device.
- the light-based positioning systems and techniques may also be used to manage and run a business.
- the light-based positioning may help keep track of inventory and to make changes to related databases of information.
- the light-positioning system may direct a person to where a particular item is located by giving directions and visual aids.
- the light positioning may even provide positioning information to direct the person to the correct shelf the item is currently residing on. If the person removes the item, the mobile device may update the inventory databases to reflect the change.
- the same function may be implemented in a store environment as merchandise locations are changed or updated. This information may then be used in providing content to a user.
- the updated location may be used to locate the item or direct the shopper to an online website to purchase an out-of-stock item.
- the mobile device using the light-based positioning technique in conjunction with a wireless connection and other information may be used to provide non-intrusive data collection on customers. The data collection of how customers move through a store and where they spend time may be used to improve layout of stores and displays of merchandise.
- the light-based positioning systems are also easy and low-cost to set up compared to other location-positioning systems. Since each light source operates autonomously, a building owner only needs to swap out existing light sources for those that provide light-based information to a camera-enabled device.
- the light sources are non-networked independent beacons that broadcast identification codes configured when manufactured. This allows the light sources to be manufactured at a lower cost compared to networked light sources. Further, the non-networked independent beacon light sources in the light-based positioning system may be easier for building owners to install.
- the light-based positioning system may also include optimizations in some embodiments. For example, location information obtained from either the identification code or from alternative techniques can be used to reduce latency in determining position information. This optimization may work through geo-fencing by constraining the search area to find information regarding the captured light sources more quickly. This can reduce the overall delay experienced by a user from the time the mobile device captures the light sources to when relevant position information is provide to the mobile device and/or relevant content is provided to the mobile device.
- beacon-based light-positioning systems are managing the additional power consumption of communication-enabled lighting devices in comparison to that of non-communicating devices.
- Lighting sources 101 in general, regardless of form factor or technology, are differentiated in part by their power consumption; generally, the less the better. Accordingly, higher energy efficiency is one of the core economic forces driving adoption of Light-Emitting-Diodes (LEDs).
- LEDs Light-Emitting-Diodes
- the power requirements tend to increase depending on the modulation scheme since energy must be divided between the carrier wave and the modulation wave.
- There are many different techniques for transmitting data through light for example, as discussed in U.S. Ser. No. 12/412,515 and U.S. Ser. No.
- FIGS. 18A-C represent several digitally modulated light sources 101 a - c with varying duty cycles; a low duty cycle 1801 , a medium duty cycle 1802 , and a high duty cycle 1803 .
- a duty cycle is a property of a digital signal that represents the proportion of time the signal spends in an active, or “on,” state as opposed to an inactive, or “off,” state.
- a light source with a low duty cycle 1801 is inactive for a high proportion of time.
- a light source with a medium duty cycle 1802 is inactive for about the same proportion of time that it is active.
- a light source with a high duty cycle 1803 is active for a high proportion of time.
- the duty cycle of a light source affects the luminosity of the light source.
- a light source having a higher duty cycle generally provides more luminosity than that same light source with a lower duty cycle because it is on for a higher proportion of time.
- Duty cycle is one aspect of a modulation scheme. Other aspects include pulse shape, frequency of pulses, and an offset level (e.g., a DC bias).
- DPR modulated light sources 101 rely on frequency modulation, they are able to circumvent the limitations of traditional AM based approaches. Note that frequency modulation in this context does not refer to modifying the frequency of the carrier (which is the light signal), but instead to modifying the frequency of a periodic waveform driving the light source.
- One popular technique for dimming LED light sources 101 is pulse-width modulation (PWM), which controls the average power delivered to the light source by varying the duty cycle of a pulse. In a DPR modulation system utilizing PWM, a DPR modulator would control the frequency of the pulses, with the duty cycle determined by the dimming requirements on the light source 101 .
- PWM pulse-width modulation
- a DPR-modulated light source having a DPR modulation frequency
- the data may include information in the form of an identifier that distinguishes a light source from other nearby DPR-modulated light sources.
- this identifier is a periodic tone that the light source randomly selects to identify itself.
- a periodic tone may be a signal that repeats with a given frequency.
- a light source may receive such an identifier from an external source.
- the modulation frequency (f) of the transmitter and the sampling time for the image sensor (T s ) of the receiver are first defined.
- the duty cycle parameters (T off ) and (T on ) that correspond to the on and off times of the light source are defined.
- T s is an important parameter because the image sensor sampling time defines a minimum amount of modulation time required to produce the banding effects which allow for the frequency detection required for DPR demodulation.
- the required modulation time may refer to either the T on portion 1804 or the T off portion 1805 of the signal; however, to maximize the brightness of the light source, T off is used as the limiting variable (if solving for the minimum duty cycle, T on may be used).
- T s of the receiving device is less than twice T off of the light source, residual banding on the image sensor will typically not take place; therefore, the signal cannot be extracted. In order for banding to occur, T s should be greater than twice the value of T off (T s >2 ⁇ T off ).
- the modulation frequency may be defined from the transmitter side and may be completely independent of the sampling time T s .
- T s is a property of the receiver, which is defined by the image sensor manufacturer and is likely not designed for optimal DPR demodulation properties.
- T s varies depending on the specific image sensor, and may be expected to change as more advanced image sensors are developed. Therefore, it is important to optimize such that a broad range of both modulation and sampling frequencies may be used.
- equations and variables for the calculation of the maximum duty cycle are described for a variety of test cases.
- T off in terms of duty cycle and modulation frequency, one may first start with the fundamental definition of what the duty cycle is: 1 minus the ratio of signal on time divided by the combination of signal on and off time.
- T off which was previously defined as a value less than twice T s , may then be used to define the maximum duty cycle for any given modulation used in DPR demodulation.
- the modulation frequency range was chosen to start at 300 Hz, which is above the range which the human eye can see.
- the modulation frequency range may range from 60 Hz to 5000 Hz.
- the image sensor sampling frequencies may range from as low as 1 KHz to as high as 1 MHz.
- the input power may be increased such that the resulting average power of the communicating light source 101 is identical to the non-communicating light source 101 .
- the average power of the two light sources will be the same, yielding a perceivably identical luminous output. Take for instance LED source “A” that is powered by 6 watts and modulated where 50% of the time it is “on”, and the remaining 50% “off”, effectively resulting in a 3-watt average power.
- this light source 101 may double the input power from 6 watts to 12 watts. While the input power of “A” was increased, the average power is halved to equal 6 watts; therefore, sources “A” and “B” appear to be identical to the human eye in terms of brightness.
- LED “droop” the input power to LED source “A” was doubled while the input power to “B” was left unchanged. Assuming that each source was supplied by a constant 12 volts, this means that the input current to source “A” had to have doubled in order to achieve the required 12 watts of power consumption. This equates to a 50% increase in current, when moving from 0.5 amperes to 1 ampere, and may only be performed if within the manufacturers' tolerable input current range for the LEDs.
- P mod may then be calculated to describe how much extra power is required to support a modulated light source 101 with regard to the duty cycle. Recall that for a modulation frequency of 2000 Hz and sampling frequencies of 20 kHz and 4 kHz, the maximum duty cycle equaled 99.25% and 96.25%.
- modulation schemes 1901 , 1902 , and 1903 depict varying duty cycles where a DC bias 1904 has been added which correspond to the modulated light sources 101 a - 101 c .
- Modulation schemes where the light source 101 does not turn all the way “off” are important when considering light source 101 brightness, efficiency, lifetime, and the signal to noise ratio (SNR) of the communications channel.
- the DC bias 1904 during modulation reduces the peak power required to drive the light source for a given brightness. A reduction in peak power will reduce the negative impact of overdriving the lighting source, which is known to cause efficiency losses known as “droop” for LEDs, in addition to decreasing light source 101 lifetimes.
- D is the duty cycle
- P on P off are the respective on/off powers.
- the impact on light source 101 brightness is that increasing the “off” power will increase the total power. This reduces the required peak power delivered to the lighting source, because the power transferred during the “off” period can make up the difference.
- a 10% increase in the “off” period power translates to a 10% decrease in the “on” period power.
- I av ⁇ V D ⁇ I on ⁇ V+(1 ⁇ D) ⁇ I off ⁇ V.
- I av D ⁇ I on +(1 ⁇ D) ⁇ I off .
- a constant current may be applied with differing voltages to achieve a similar effect.
- Another major requirement for DPR modulation is to interface with existing light dimmers.
- light source 101 dimmers employed on the commercial market.
- One popular dimming technique is triac dimming.
- a triac dimmer a variable resistor switch is used to control the amount of power delivered to the light source 101 over the AC line.
- LED light sources 101 it is necessary to put a special driver between the triac dimming circuit and the LED source. This is because LEDs are current-driven devices, and thus require an AC/DC converter to transform AC from the power lines to a DC current for driving the LEDs.
- FIG. 20 demonstrates a system by which a DPR modulator may interface with existing lighting control circuits.
- a dimmer controller 2002 sends a dimmer signal 2003 to a dimmable LED driver 2006 .
- the dimmer signal would be transmitted across the AC power line.
- the dimmable LED driver 2006 then converts the dimmer signal to a pulse width modulated signal used for driving the light output 2007 of the source 2001 .
- the configuration of the system diagram shows the dimmer signal 2003 going to both the DPR modulator 2004 and the LED driver 2006 ; however, this does not always need to happen.
- the LED driver 2006 may contain a “master override” input that is designed to supersede any dimmer signal 2003 input. In this case, the dimmer signal 2003 still goes to the LED driver 2006 , but is ignored. In other cases where there is not an override input, the dimming signal only goes to the DPR modulator.
- DPR modulator 2004 is responsible for sending DPR signals 2005 to the LED driver 2006 that controls the light output 2007 .
- DPR modulator 2004 controls the frequency of the PWM signal and selects the desired value.
- the width of pulses in signals 1801 - 1803 are determined based on dimmer signal 2003 , which indicates the desired light source 2001 brightness level. Note that the dimmer controller 2002 is not contained within the light source 2001 , and may output a variety of dimmer signals 2003 (triac, or a proprietary method).
- the DPR modulator 2004 is responsible for interpreting these different signals and appropriately outputting a DPR signal 2005 that corresponds to the desired brightness level of the inputted dimmer signal 2003 .
- the DPR modulator 2004 interfaces directly with the LED driver.
- the DPR modulator 2004 may also be contained inside the LED driver 2006 as part of an integrated solution instead of as a separate component.
- FIG. 21 contains a high level overview of a DPR modulator 2004 .
- Data 2101 is first sent to DPR tone generator 2102 .
- Data 2101 may contain information from any source.
- data may include the identifier for the light.
- DPR tone generator 2102 converts the data 2101 into a sequence of DPR tones.
- a DPR tone is a periodic digital signal that oscillates between active and inactive states with a particular frequency. This process is described further in FIG. 22 . Depending on the requirements of the data transmission channel, this could either be a single tone (suitable for a beacon based positioning system using light identifiers), or a sequence of tones (if higher data rates are desired by the end user).
- the DPR Tone(s) 2203 are then sent to the waveform generator 2103 , which is responsible for generating the DPR signal 2005 for driving the LEDs.
- Waveform generator 2103 receives a dimmer signal 2003 input from a dimmer controller 2002 , which controls the brightness of the light source.
- dimmer controller 2002 would control the duty cycle of square wave 1802
- DPR Tone(s) 2203 would control the frequency of the square wave.
- the result is an output DPR signal 2005 , which is then sent to the LED driver 2006 .
- FIG. 22 contains a breakdown of DPR Tone Generator 2102 .
- This module is responsible for taking a piece of data and converting it to a sequence of DPR tones.
- a DPR tone determines the frequency at which a waveform, such as the square waves from FIG. 18 , is sent.
- the range of possible tones, defined here in as T 0 through T n is determined by both the sampling time, T s , of the image sensor (as discussed in paragraph 0006), and the frequency response of the light source 101 .
- Encoder 2201 is a standard base converter—it takes a piece of data in binary and converts it into a corresponding DPR tone.
- a typical range for tones created by DPR Tone Generator 2102 is 300 Hz-2000 Hz, in steps of 10 Hz, allowing for 170 distinct DPR tones.
- the step size between tones is selected to reduce noise, and depending on the requirements could be much higher or lower than 10 Hz.
- that data 2101 may contain an identifier of value 10 for light source 101 .
- This identifier is passed to Tone(s) Generator 2102 , which generates (or selects from memory) a sequence of tones.
- the length of a DPR tone sequence could be as low as 1 (in the case of a single tone used in a beacon-based positioning system).
- an identifier of 10 would map to a DPR tone of 400 Hz.
- DPR Tone Generator 2102 could either store the identifier in memory beforehand, using pre-computed mappings of data to tone sequences, or alternatively it could compute this on the fly. The exact method of generating the sequence of tones may be driven by the resources available on the light source 101 . Once one of the possible tones sequences 2202 is created, it is sent to Waveform Generator 2103 .
- FIG. 23 contains the breakdown of Waveform Generator system 2103 , which combines a tone sequence 2202 with a waveform from symbol creator 2303 and dimmer signal 2003 to create a DPR signal 2005 for driving light source 101 .
- the resulting waveform will be periodic, with a frequency defined by the sequence of tones, a symbol created based on the list of possible symbols in symbol creator 2303 , and an average output (brightness) determined by the dimmer signal 2003 .
- This desired brightness could either be hard-coded on the module, or provided as an external input through a dimming control module.
- the choice of a symbol is determined within Symbol Selector 2301 , which generates a control line 2302 for selecting a symbol from symbol mux 2402 .
- FIG. 24 contains the breakdown of Symbol Creator 2303 , which holds possible symbols 2401 a - 2401 d . These could include a saw tooth wave 2401 a , sine wave 2401 b , square wave 2401 c , and square wave with a DC offset 2401 d , or any other periodic symbol. Symbol creator then takes in a selected symbol 2402 , and modifies it such that a desired brightness 2106 is achieved. In the case of a square wave symbol 2401 c , dimmer signal 2003 would modify the duty cycle of the square wave. The resulting waveform is then sent to output signal 2005 for driving the light source.
- the goal of the output waveform 2105 which drives light source 101 , is to illuminate a scene in such a way that the DPR modulated signal may be picked up on any standard mobile device 103 .
- Reducing flicker on video which is under illumination from fluorescent lamps is a well-known problem.
- the flicker is caused by periodic voltage fluctuations on the AC line powering the lamp.
- the luminance level changes at 100 Hz.
- This causes alternating white/dark bands to appear in video recorded with CMOS imagers.
- the bands are a result of the rolling shutter mechanism on CMOS imagers, which partially expose different areas of the image at different points in time.
- the lines on the image may occur on both, one, or on multiple frames, and may appear to move in time. See, for example, U.S. Pat. No. 6,710,818, the entire contents of which is hereby incorporated in its entirety, which describes methods for detecting and removing this unwanted effect.
- Possible algorithms for mitigating flicker include automatic exposure control, automatic gain control, and anti-banding. These techniques are common in many mobile devices as a means to remove flicker caused by fluorescent lamps.
- DPR demodulation instead of removing flicker, exploits the rolling shutter effects of CMOS cameras as a means of transmitting data.
- a CMOS device with a rolling shutter captures an image frame by sequentially capturing portions of the frame on a rolling, or time-separated, basis. These portions may be vertical or horizontal lines or “stripes” of the image that are captured at successive time intervals. Because not every stripe is captured in the same time interval, the light sources illuminating the image may be in different states at each of these time intervals. Accordingly, a light source may produce stripes in a captured frame if it is illuminated in some time intervals and not illuminated in other time intervals. Light sources that broadcast digital pulse recognition signals may produce patterns of stripes.
- image processing techniques may be used to deduce the illumination frequency based on the width of the stripes. For example, consider a room containing five light sources 101 , each broadcasting at 500 Hz, 600 Hz, 700 Hz, 800 Hz, and 900 Hz, respectively. Each distinct frequency, otherwise known as a DPR tone, may be used to identify the light source 101 .
- a mobile device receiver within view of the transmitting lights can detect the DPR tones, correlate an identifier associated with the tone, and then use a lookup table to determine the location of the device based on the location associated with the identifier(s).
- FIG. 25 is a continuous time representation 2501 of how an individual row on a rolling shutter image sensor is sampled.
- the exposure time interval 2502 represents the period over which light accumulates on the photo sensor. If the exposure time is much lower than the period of the DPR modulated signal, the light and dark bands will be clearly defined. If the exposure time is longer, the light and dark bands will lose their definition.
- FIG. 26 contains a continuous time example 2601 of a DPR modulated light signal.
- the signal is a square wave with a 50% duty cycle being driven at a DPR tone of 300 Hz.
- the relationship between the DPR illumination period 2602 and the exposure time 2502 determines how well defined the bands are on the received image.
- FIG. 27 is the continuous time sampled image 2701 , created by convolving an individual row sampling function 2501 with a DPR modulated signal 2601 .
- the alternating periods of high brightness 2702 and low brightness 2803 are caused by the DPR modulation frequency, and appear as alternating white/dark bands on the received image.
- FIG. 28 is a representation of a discrete time-domain signal model 2801 for representing how a rolling shutter on an image sensor samples the incoming light pulses 2601 .
- the rolling shutter is modeled as an impulse train, containing a sequence of the Dirac Delta functions (otherwise known as a Dirac comb). Each impulse is separated by an interval, T, which corresponds to the speed of the rolling shutter commonly found in most CMOS image sensors.
- the interval T varies from device to device which causes the bands on scenes illuminated by DPR modulated signals to vary in size.
- the mobile device 103 preferably accounts for hardware-dependent factors (e.g., rolling shutter speed) to properly determine the DPR tone.
- FIG. 29 contains a discrete time representation 2901 of the rolling shutter sampling functionality over multiple frames.
- DPR demodulation on current imaging technology is capable of much higher data rates than modulation schemes that sample on a per-frame basis.
- the sensor would capture 480 samples per frame (represented as 480 consecutive delta functions in sensor model 2801 ).
- a demodulation scheme using a global shutter would only be capable of taking one sample per frame. This is a key advantage for indoor positioning using beacon-based broadcasting schemes because the time-to-first-fix is orders of magnitude faster than competing technology, which may take several seconds to receive a signal. For example, consider a typical mobile device 103 camera which samples at 30 frames per second (FPS).
- FPS frames per second
- time-to-first-fix may be achieved with as little as a single frame, or 1/30 of a second, versus 1 second for a demodulation scheme that samples on a per-frame basis. This compares to a time-to-first-fix of up to 65 seconds for GPS, 30 seconds for assisted GPS, and 5-10 seconds for WiFi positioning.
- DPR demodulation may be performed on the mobile device itself, versus the server-side processing required for WiFi fingerprinting algorithms.
- client-side processing provides a major advantage.
- image sensors will have much higher frame rates.
- DPR demodulation may be adjusted to sample on a per-frame basis, instead of a rolling shutter basis.
- the key principle is that the demodulator may be adjusted in software, allowing future mobile devices to tune their receiving characteristics to receive DPR signals.
- the software adjustments that need to be applied are the subject of the following sections.
- the device In order to prepare a mobile device 103 to receive the modulated DPR signals 2105 , the device is first configured. This is to counteract the flicker-mitigation algorithms typically applied in mobile device image sensors.
- FIG. 30 describes the method by which mobile device 103 is configured to receive DPR modulated signals.
- the initialize sensors 3001 function initializes and activates the available sensors capable of receiving data. For typical modern mobile devices these would include both the front- and rear-facing cameras.
- a “front-facing” camera or other sensor of a mobile device is one that is mounted on the same side of the device as its display and is therefore likely to face toward a user.
- the rear-facing camera or another rear-facing is used because it is more likely to have a view of the user's surroundings that is relatively unoccluded by the user's own body and thus to record light cast directly by local light sources.
- Determine sensors to modify 3002 then decides which sensors need to be modified. A number of possible factors determine whether or not a particular sensor should be initialized then modified, including power consumption, accuracy, time since last reading, environmental conditions, required location accuracy, and battery state.
- Modify sensors 3003 then passes a list of the appropriate sensors which need to be modified to a function which has additional information about the mobile device 103 and adjusts the demodulation scheme for device specific limitations 3004 .
- possible sensor parameters to modify include exposure, focus, saturation, white balance, zoom, contrast, brightness, gain, sharpness, ISO, resolution, image quality, scene selection, and metering mode.
- sensor parameters such as exposure, white-balance, and focus are locked to prevent further adjustments.
- One challenge is overriding the automatic parameter adjustments that mobile operating systems typically provide as part of their camera application programming interfaces (APIs).
- APIs camera application programming interfaces
- the sensor settings are adjusted automatically depending on factors such as but not limited to ambient light conditions, areas of focus, distance from objects, and predetermined scene selection modes. For instance, when taking a picture with an image sensor, if the scene is dark then the exposure time is automatically increased. When taking picture of a scene mode with fast moving objects, the exposure time is usually decreased.
- FIG. 31 contains a process for modifying the various sensor parameters contained in a mobile device 103 in a way that overcomes the limitations imposed by current camera APIs.
- the first step is to initialize the required sensors 3001 .
- this involves setting the frame rate, data format, encoding scheme, and color space for the required sensors.
- the algorithm searches for regions of interest 3101 . In the case of setting the exposure using metering, these regions of interest 3101 would be the brightest regions of the image.
- Set metering area 3102 sets the metering area to the brightest portion, effectively “tricking” the mobile device 103 into lowering the exposure time.
- Lock parameter 3103 then locks this exposure time to prevent the auto-adjustment feature of the camera from overriding the manual setting.
- adjust for hardware dependent parameters 3104 accesses a lookup table and adjusts the demodulation algorithm based on hardware and software differences. For the case of an image sensor, one example of this is changing the sampling time based on the rolling shutter speed of the device. This rolling shutter speed may either be loaded from a lookup table beforehand (using predetermined values) or measured on the fly. Each device only needs to measure its rolling shutter speed once per image sensor. Once parameters set? 3105 is satisfied the algorithm ends; otherwise, it returns to identify regions of interest 3101 .
- the method of exploiting the metering area on a mobile device 103 may be used to optimize many of the required parameters in addition to the exposure, including white balance, contrast, saturation, ISO, gain, zoom, contrast, brightness, sharpness, resolution, image quality, and scene selection. Furthermore, these parameters could already be known beforehand, as each mobile device 103 will have its own “device profile” containing the optimal camera settings. This profile could be loaded client side on the device, or sent over a server. Note that although the method of using the metering area to control the exposure may improve the performance of DPR demodulation, it is not strictly necessary. Simply locking the exposure 3103 is often sufficient to prevent the automatic camera adjustments from filtering out the DPR signals.
- FIG. 32 describes a process for decoding the information contained inside a DPR modulated signal. Identify regions 3201 is used to separate different regions on the image illuminated by DPR signals. At the base level, the region of interest is the entire image. However, when one or more light sources 101 are present, there exists an opportunity to receive multiple DPR signals simultaneously. In this scenario, the sensor effectively acts as a multiple antenna receiver.
- Such multiple antenna systems more generally referred to as multiple-input multiple-output (MIMO), are widely used in the wireless networking space. This is an example of spatial multiplexing, where wireless channels are allocated in space as opposed to time or frequency.
- MIMO multiple-input multiple-output
- MIMO for DPR demodulation in a beacon-based light-positioning system
- a mobile phone user receives DPR modulated signals on a photodiode array (such as an image sensor, or any imaging technology that contains multiple spatially separated sensors)
- the DPR signals will each appear at different locations on the sensor.
- Each region 3201 of the image may then be processed independently, in the same way that each mobile phone user in a cell network only connects to the cell they are closest to.
- detect frequency content 3202 identifies the presence of DPR tones from the sensor data. Described here are multiple methods for extracting the frequency content from a DPR signal. One possibility is to use line-detection algorithms to identify the pixel width of the stripes, which directly corresponds to the transmitted frequency. This stripe width is then used to access a lookup table that associates width and transmitted frequency and determines the transmitted tones. Possible methods for detecting lines include Canny edge detection, Hough Transforms, Sobel operators, differentials, Prewitt operators, and Roberts Cross detectors, all of which are well developed algorithms, known to those of skill in the art.
- Adjust for dependent parameters 3004 modifies the appropriate camera sensors for optimal DPR demodulation. In the case of line detection, this corresponds to a linear adjustment for the line width lookup table.
- Determine tones 3203 uses the adjusted line width to determine the DPR tone sent. This process is performed for each region on the image, until there are no more regions 3204 remaining. A data structure containing all the regions, with their associated identifiers, is then returned 3205 .
- FIG. 33 An additional method for performing DPR demodulation is described in FIG. 33 .
- One or more light sources 101 illuminates a scene 3301 .
- the image sensor on mobile device 103 acquires a sequence of images 3302 , the brightness of any given pixel depends on both the details of the scene as well as the illumination.
- “scene” refers to the area within view of the camera. The scene dependence means that pixels in the same row of the image will not all have the same brightness, and the relative brightness of different image rows is not solely dependent on the modulated illumination 3301 . If one were to take the Fourier transform of such an image, both the frequency content of the illumination, as well as the frequency content of the underlying scene, will be present.
- the contribution of the scene may be removed using a background subtraction algorithm 3303 .
- the “background” is the image that would result from un-modulated illumination as opposed to the effects of modulated illumination 3301 . Subtracting the background from an image leaves only the effects of illumination modulation.
- One possible implementation of a background subtraction method uses a video sequence. If a video of a scene illuminated with modulated light is recorded, the light and dark bands may appear at different locations in each frame. For any modulation frequency that is not an exact multiple of the video frame rate, there will be a resulting beat frequency between the video frame frequency and the illumination modulation frequency.
- the illumination signal will be in a different part of its period at the beginning of each frame, and the light and dark bands will appear to be shifted between video frames (i.e. the bands will appear to move up or down across the scene while the video is played).
- this algorithm is described with the use of a video sequence, other embodiments may perform background subtraction using still images.
- the bands move between video frames, the average effect of the bands on any individual pixel value will be the same (assuming that in a long enough video each pixel is equally likely to be in a light or dark band in any given frame). If all the video frames are averaged, the effects of the bands (due to the illumination modulation) will be reduced to a constant value applied to each pixel location. If the video is of a motionless scene, this means that averaging the video frames will remove the effect of the bands and reveal only the underlying scene (plus a constant value due to the averaged bands). This underlying scene (the background) may be subtracted from each frame of the video to remove the effects of the scene and leave only the effects of illumination modulation 3301 .
- FIG. 34 contains an implementation of a possible background subtraction algorithm 3304 .
- a frame buffer 3402 accumulates video frames 3401 .
- the size of this buffer can vary, depending on the memory capacity of mobile device 103 and the required time to first fix.
- Frame averaging 3403 computes the average based on the frames in the buffer 3402 .
- the average of these frames is used to generate background frame 2704 .
- the background frame may be acquired using a number of different averaging techniques 3403 , including a simple numerical average, a normalized average (where each frame is divided by the sum of all the frames), Gaussian averaging, or by doing a frame difference between subsequent frames.
- a frame difference simply subtracts subsequent frames from one another on a pixel-by-pixel basis.
- FIG. 35 describes a technique for dealing with motion between frames, which is a likely scenario when demodulating DPR signals on mobile device 103 .
- Motion compensation 3501 is necessary to best determine the underlying scene. By determining the motion between video frames (for example, shifting or rotation of the whole scene due to camera movement), each video frame may be shifted or transformed such that it overlies the previous frame as much as possible. After performing these compensatory transforms on each frame in motion compensation 3501 , the video frames are averaged 3403 to get the scene background 3404 .
- Phase correlation is one possible method of estimating global (i.e., the whole scene moves in the same way, as in the case of camera motion while recording video) translational motion between frames.
- the 2D Fourier transform of a shifted image will be the same as that of the original image, except that a phase shift will be introduced at each point. Normalizing the magnitude of the 2D Fourier transform and taking the inverse transform yields a 2D image with a peak offset from the center of the image. The offset of this peak is the same as the shift of the shifted image.
- additional methods for motion compensation 3501 include Kernel Density Estimators, Mean-shift based estimation, and Eigenbackgrounds.
- FIG. 36 contains a sample image 3601 of a surface illuminated by a light source undergoing DPR modulation. The image is being recorded from a mobile device using a rolling shutter CMOS camera. The stripes 3602 on the image are caused by the rolling shutter sampling function, which is modeled in by the sequence of Dirac Combs 2801 in FIG. 28 .
- FIG. 37 shows the result 3701 of performing background subtraction on the raw image data from FIG. 36 .
- Background subtraction is used to extract the stripes from the raw image data.
- the result is an image of alternating black/white stripes that represents the discrete time-domain representation of the transmitted DPR signal.
- the stripes 3702 are much more pronounced than in the raw image data from FIG. 36 due to the improvement from background subtraction.
- Illumination modulation affects each row of a video frame identically, but imperfect background subtraction may lead to non-identical pixel values across image rows. Taking the Fourier transform of row values along different image columns, then, may produce different illumination signal frequency content results. Because the true illumination signal frequency content is the same for the entire image, a technique to reconcile these different results may be employed.
- One possible method is to assign the average pixel value for any given row to each pixel in that row. This method takes into account the information from each pixel in the row, but by yielding uniform row values gives a single illumination signal frequency content result when taking the Fourier transform of row values along an image column.
- FIG. 38 displays the results of applying row averaging 3801 to the background subtracted image 3701 . The stripes 3802 are much more visible as a result of the row averaging, and they are also more consistent across rows.
- FIG. 39 shows the Fourier transform 3901 of the row averaged image 3801 from FIG. 38 .
- the peak frequency is used to identify the sequence of tones, and thus the transmitted identifier.
- FIG. 40 shows the Fourier transform 4001 from FIG. 39 after applying a high-pass filter.
- the DC component of the signal is removed, which allows a peak frequency detector to move to detection of the DPR tone frequency.
- FIG. 41 shows a 2-D Fast Fourier Transform 4101 of the post-processed DPR modulated signal data 3701 .
- 2-D Fourier analysis of the DPR modulated signal 3601 may also be performed.
- 2-D Fourier Analysis is a popular and widely used technique for image analysis. Because there are a number of software libraries that are highly optimized for performing multidimensional FFTs, including OpenCV, multidimensional Fourier analysis is a viable alternative to the 1-D analysis.
- the DPR tones 4102 may be easily seen across the vertical axis 4103 of the 2-D FFT. Brighter areas on the FFT image 4101 correspond to areas on the image with higher spectral content. A peak may be seen at the origin 4104 , which corresponds to the DC component of the DPR signal.
- FIG. 42 shows a low-pass filtered version 4201 of the 2-D FFT 4101 .
- the filtered image 4201 contains dark areas 3502 at the higher frequencies on the image.
- the low pass filter rejects the higher frequencies. This is a key component of successful DPR demodulation. As discussed previously, DPR modulation relies on transmitting digital signals at different frequencies. When using Fourier analysis on these signals, higher frequency harmonics appear, in particular at higher duty cycles. These higher frequency components act as noise in the signal, so removing them with filtered image 4201 is one technique for recovering the transmitted tones.
- FIG. 43 shows a high-pass filtered version 4301 of the 2-D FFT 4101 .
- the dark area 4302 at DC demonstrates the result of the high-pass filter, which rejects the DC noise component.
- the higher frequency bands 4303 are still contained in the signal, allowing the demodulator to determine the peak frequency.
- beacon based light positioning system An important consideration in the design of a beacon based light positioning system is the choice of light identification codes with respect to the system layout.
- DPR digital pulse recognition
- FIG. 1 which contains light sources 101 a - d , each with its own DPR tone.
- Spectral leakage is a well-known phenomenon associated with Fourier analysis. It is a consequence of the finite observation time over which a signal is measured. For DPR demodulation that exploits the rolling shutter, this finite time corresponds to the period of the rolling shutter. Spectral leakage negatively impacts the ability to distinguish two or more frequencies, so in the case of user 102 receiving multiple DPR tones, the ability to distinguish tones will be diminished. In some cases, the tones will be unresolvable, which could possibly cause dead spots in the beacon based positioning system presented in FIG. 2 .
- spectral leakage can be mitigated in a number of ways.
- One technique is the use of a digital filter, which is sometimes referred to as a window function.
- Window functions include Rectangular, Hann, Hamming, Turkey, Cosine, Kaiser, and Gaussian windows. Using a window function allows one to improve the spectral resolution of the frequency-domain result when performing Fourier analysis.
- a simple approach to reduce the impact of spectral leakage is to control the spatial distribution of bulbs. For example, one could come up with a rule which says that no two adjacent bulbs can have a DPR tone within 50 Hz of another adjacent bulb. For most lighting topologies 4403 , mobile device users 4402 a - b will see at most two adjacent lights at the same time. If the DPR tones are distributed such that adjacent bulbs are dissimilar enough, then the individual DPR tones can be resolved.
- adjacent light sources could destructively interfere with each other.
- the two light sources 4401 a and 4401 b in FIG. 44 each transmit multiple DPR tones.
- Light source 4401 a emits 300 Hz, 400 Hz, and 500 Hz
- light source 4401 b emits 500 Hz, 600 Hz, and 700 Hz.
- both sources share a common tone of 500 Hz. Since the bulbs are typically non-networked, their emissions are not synchronized. Accordingly, if the common 500 Hz tones are out of phase with one another, they will destructively interfere, possibly resulting in a missed detection.
- FIG. 47 depicts a user commissioning a beacon based light positioning system. Commissioning refers to the process of acquiring of acquiring DPR signals being emitted from light sources 4401 a - 4401 b , and then georeferencing the light sources.
- Mobile device user 4702 a invokes an application running on their mobile device 4703 .
- the application listens for the DPR signals using sensors on the device.
- the mobile device detects a valid DPR signal
- the user is prompted to georeference the light source. This could be done by simply entering in coordinates (which could take the form of latitude, longitude, and altitude), or some arbitrary coordinate system.
- the user could also assign the coordinates by dragging and dropping the light location on a map. Once the coordinates are assigned, they can be sent to a remote database 802 for storage.
- the database contains records which associate the light identifier with the light location.
- a user interface developed for this task is presented in FIG. 48 .
- a user georeferersces light source 4401 a , they proceed in a path 4704 a underneath additional light sources 4401 a - c . For each light source, as they successfully detect the source, they are prompted to georeference the light. If the user attempts to add a light source that violates the rules for the lighting topology (as in the previous example, where adjacent lights are not allowed to contain DPR tones less than 50 Hz apart), the user would be prompted to change the location of the light source before adding it to the map.
- FIG. 47 also contains a situation by which multiple users 4701 a - b can commission a space simultaneously. Note that the number of users could be much larger than two, especially in the case of a large space. Having multiple users operate at the same time greatly speeds up the commissioning process.
- users 4701 a and 4701 b move about their respective paths 4704 a and 4704 b , they georeference the light locations in the same manner that an individual user would. Each time the user adds a light, the light could be sent to a remote server 703 for storage. The connection to the server could be done through any standard network connection. Mobile devices 4702 a - b would each write their respective portions of the georeferenced light positions to the server.
- each mobile device user 4702 a - 4702 b would maintain a synchronous representation of the current light georeferencing. In this scenario, when mobile device user 4702 a adds a light to the database, mobile device user 4702 b would see that light location appear on their device. This helps to avoid the need for the users to maintain close communication during commissioning, thereby speeding the process along. In another embodiment, mobile device users 4702 a - b would each maintain their own separate records of the light locations.
- the remote server 703 received the commissioning data from, each user, it would then take all of the data as input and determine the best result. For example, in one embodiment the server would take a simple numerical average of the coordinates for each light. By combining data from many users when commissioning a space, the accuracy of the system is improved.
- the users are depicted as the ones commissioning the space.
- this commissioning could be performed automatically by a non-human entity, or robotic agent that patrols the space.
- the robot can use forms of inertial navigation techniques and sensor fusion to maintain an estimate of its current position.
- the robot must first be assigned an initial location fix, which could be done through a manual input, or a location fix acquired from an alternative positioning technique such as WiFi, Bluetooth, GPS, A-GPS, Ultrasound, Infrared, NFC, RF-ID, a priori known location, or markers in the visible or non-visible spectrum.
- an alternative positioning technique such as WiFi, Bluetooth, GPS, A-GPS, Ultrasound, Infrared, NFC, RF-ID, a priori known location, or markers in the visible or non-visible spectrum.
- the robot receives a light identifier from light source, it then uploads the identifier along with its estimated position to the light location database.
- the robot can also send an estimate of the strength of the current signal, along with an error estimate of its current position, as well as any additional relevant information.
- the server can then combine all of this information to get a more accurate estimate of the light position. This is analogous to the way the server combined information from multiple users in FIG. 47 .
- FIG. 48 contains one possible user interface for commissioning a space in a light positioning system.
- mobile device users 4702 a - b commission a space using mobile devices 4703 a - b .
- the mobile devices 4703 a - b presents location information, such as a map 4806 , of the space.
- a user notification such as an add button 4801 , becomes active on the user interface.
- the user can then add the light onto the map by “dragging and dropping,” using either a point and click gesture with a mouse, keyboard based commands, a touchscreen, or other such user interfaces that are available.
- an icon 4804 appears to mark its location.
- Additional user feedback such as making the device vibrate or change color, can be used to make the experience more tactile.
- the user can use the move button 4803 to move the location of the light in the space.
- additional information such as an architectural, electrical, or mechanical building plan can be used to assist in light placement or to automate fine tuning of the process.
- the user can edit and delete lights from the map using the Edit button 4802 .
- the marker 4804 Once a light is placed on the space, and the marker 4804 has been assigned a location, the marker may change its visual look 4805 when the user walks underneath the appropriate light and successfully receives the DPR signal.
- the visual feedback could include changing the color, shape, or moving the marker around on the screen. This makes it easier for the user to verify the position and identification code of the light after they have commissioned the space.
- One aspect of DPR demodulation in a light positioning system includes adjusting receiver parameters depending on specific characteristics of mobile device 4901 .
- parameters such as rolling shutter speed, frame rate, and exposure time can all vary across different hardware platforms. In order to compensate for these differences, adjustments can be created in software.
- a device profile can include all the relevant information regarding the receiver parameters of a mobile device 4901 .
- this device profile could include the exposure time, sampling frequency, number of image sensors, or other hardware dependent parameters for a specific version of mobile device 4901 .
- the mobile device performs DPR demodulation as part of a light positioning system, the device profile is first loaded. The profile could either be fetched from a remote server, or stored locally on the device. The parameters contained within the device profile are then fed as inputs into the demodulation algorithm.
- Device profiles can either be created in a number of different ways.
- the device profile could be created via manual input of values.
- a system administrator could acquire device information using sensor datasheets, or other sources, and then manually input the parameters into the database.
- the mobile device can utilize a self-calibration algorithm to figure out its own device profile. For example, consider a mobile device, with an unknown device profile that is positioned within view of a DPR modulated light source emitting a known tone. The mobile device could enter as an input the tone which it is supposed to be seeing, and then adjust its own device parameters such that the output of the detection algorithm is equal to the tone that is “known.”
- Self-calibration is another technique for resolving differences between device hardware and software.
- a special calibration frequency can be transmitted at the beginning of a DPR packet, allowing the mobile device 103 to measure its own sensor parameters, such as the shutter speed, and adjust accordingly.
- the downside to this approach is increased read time on the receiver, because the calibration frame carries no positioning information.
- a DPR modulated signal When captured by a rolling shutter image sensor, a DPR modulated signal produces periodic horizontal bands that overlay the entire 2D content of a given scene.
- k BL arg ⁇ ⁇ min k ⁇ [ k low , k high ] ⁇ ( Var ⁇ ( p 0 , ... ⁇ , M - 1 k ) ) ( 5 )
- FIG. 50 shows a plot of variance in parameterized phase vs. possible modulation frequencies, in the presence of a 755 Hz modulating source. Note that the dip 5002 at modulation frequency 755 Hz indicates the signature of the DPR modulated signal.
- DFT Discrete Fourier Transform
- the magnitude spectrum in FIG. 51 is convolved with a 3 ⁇ 3 filter kernel with the general structure presented in FIG. 52 .
- FIG. 53 shows the result of applying the above filter kernel to vertical frequency components of the magnitude spectrum in FIG. 51 .
- f[m,n] denotes an M ⁇ N frame (M columns, N rows).
- ⁇ circumflex over (f) ⁇ [m,n] denotes a vertically-windowed version of f[m,n].
- k BL arg ⁇ ⁇ min k ⁇ [ k low , k high ] ⁇ ( Var ⁇ ( p ⁇ 0 , ... ⁇ , M - 1 k ) ) ( 6 )
- dip quality measure ( q l +q r )/2 (7)
- ⁇ s denote the row sampling frequency of the rolling shutter image sensor.
- the DPR modulation frequency ⁇ corresponding to k BL, h is then given by
- ⁇ s can be determined experimentally by calibrating detection results obtained for a known modulation signal.
- one aspect of the process is to identify which sensors to use. Because many mobile devices 103 contain multiple sensors (for example, consider smartphones that contain both front and rear cameras), some embodiments include an algorithm to decide which camera sensor to use at a particular point in time. For example, consider the situation in FIG. 47 , where a user 4702 a is walking underneath light source 4401 a , emitting a DPR modulated spot signal onto the floor 4701 . The user's mobile device 4703 a contains both a front and rear camera. As the user walks past the DPR illuminated spot 4701 , the rear camera is the first sensor to capture the image. When the user walks further along, the front facing camera is positioned underneath the light. In this scenario, some embodiments use an algorithm to decide which camera to use when receiving the light signals.
- FIG. 55 contains an implementation of a smart camera switching algorithm.
- Select sensors 5501 first decides which sensors to use. The decision for what sensor to use depends on a number of factors. In one embodiment, the mobile device could use information about its orientation, using sensor readings gathered from the gyroscope, compass, accelerometer, or computer vision, and then use that to determine which camera to choose. For example, if the device were to recognize that it was oriented such that the rear camera was facing the ceiling, select sensors 5501 would first choose the rear sensor to receive the beacon based light positioning signal, as opposed to defaulting to the front camera. After selecting a sensor 5501 , initialize sensors 3001 sets the required hardware and software sensor parameters as described in FIG. 30 .
- Tone (s) Detected? 5502 implements a DPR demodulation algorithm to analyze incoming image/video frames for the presence of DPR tones.
- An output of the DPR demodulation algorithms is a confidence score representing the likelihood that a DPR tone is present in the received images. If Tone(s) Detected? 5502 returns TRUE, then the algorithm terminates. If Tone (s) Detected? 5502 returns false, Continue Checking? 5503 decides whether or not to try the remaining camera sensors. The decision is governed by factors including battery life, location refresh time, and accuracy requirements. If Continue Checking? 5503 continues the algorithm the cycle repeats, otherwise it is terminated.
- the primary functionality of most image sensors on mobile devices is recording multimedia content in the form of video or photographs. In those use cases, it is desirable to display a preview feed of what the camera is recording before actually shooting the video/photo. On most mobile device's 103 , displaying this preview feed is the default mode when using the camera. On some mobile device API's, the software actually requires the application to display a preview feed such that if a feed is not being displayed, the device is not allowed to record data.
- a mobile device 103 For a mobile device 103 that is receiving DPR modulated light signals, it is desirable to hide the camera feed during DPR demodulation. For example, consider the case of a user walking around a retail store, using an in-store map to discover where items are within the store. If the mobile device application framework required the camera preview to be displayed, it would interrupt the user's interaction with the mobile app. Furthermore, since there are a number of different camera tweaks that can be applied during DPR demodulation (for example, modifying the exposure, focus, zoom, etc.), the camera preview image quality would be low.
- the mobile device creates a surface that is a single pixel in size, and then passes this surface as the camera preview.
- the surface is an area on the mobile device for displaying information to a user. This fulfills the requirement of the mobile device API that it is presented a surface to write to. Because the surface is only a pixel wide, the present system effectively tricks the API, since the mobile device user cannot see the individual pixels surface. In another embodiment, the mobile device simply does not create a camera preview surface.
- DPR demodulation algorithms One aspect of DPR demodulation algorithms is that the performance of such algorithms varies from location to location. For example, consider a situation in which the floor of a building contains stripes or other noise generating artifacts. The presence of artifacts on the floor adds significant noise into the DPR signal. As discussed previously, both the front and the rear camera can be used to recover DPR modulated signals. However, in a situation with the presence of noise on the rear camera, it would undesirable to use the rear camera at all. To account for situations such as this, the present disclosure could use location-dependent demodulation algorithms. Using algorithm performance information gathered from mobile device users 4402 a - b , the remote server 703 maintains records of which algorithms perform the best in various situations.
- phase variance algorithm has better performance on the front camera versus the rear camera.
- FIG. 54 A method for intelligently choosing the appropriate demodulation to use in a given scenario is presented in FIG. 54 .
- an image sensor is selected and sampled 5401 .
- This image sensor could be one of many sensors on the device (for example, either the front or rear sensor).
- An algorithm for actually selecting the sensor is presented in FIG. 55 .
- a demodulation algorithm is chosen 5402 .
- the mobile device 103 can send a request to a remote server 703 to find out which algorithm is appropriate for its current environment.
- the algorithm is implemented and the quality of the signal is reported 5403 .
- the quality of the signal is measured using a number of different metrics, as described previously.
- the algorithm might be adjusted 5404 . Adjustments to the algorithm could include changes to algorithms parameters such as the sampling rate, exposure time, or other such parameters as described previously. The adjustments also can include changing the actual choice of algorithm.
- Movement Detected/Environment Change? 5405 is used to determine whether or not the mobile device has changed its location. If the mobile device changes location, the image sensor is initialized and the sampling algorithm resamples at the beginning.
- a mobile device receiver can receive signals from multiple lights simultaneously.
- Mobile device user 5701 is within view of light spots 5702 a , 5702 b , and 5702 c . Because the user 5701 is not positioned directly underneath any particular light, it is desirable to use the relative signal strengths for each light to interpolate the position of the mobile device receiver 5703 from the lights.
- a mobile device 5703 detects quality signals from two light sources 5702 a and 5702 b . For each quality signal, the magnitude of the signal is taken into account before resolving the exact location.
- a simple algorithm is to take the average of the light locations, each weighted by the total signal strength. For a given set of n magnitudes m a and light coordinates x a , the position of the mobile device 5703 is x, where:
- Each coordinate is weighted against the total sum of signal strengths as part of the averaging process.
- the result is a set of coordinates that indicate the user's position.
- the mobile device 5703 In addition to weighting the total signal strength, the mobile device 5703 also can use information gathered from multiple image sensors, as well as information about the geometry of the room and the orientation of the device, to improve the positioning calculation. At this point, the device will have resolved a separate coordinate for the rear camera, and for the front camera. The device lies somewhere in between these coordinates. Using the geometry in FIG. 6 described U.S. patent application Ser. No. 13/526,773 filed Jun.
- an initial, broad location can be determined using geofencing. This is done via the GPS sensor of the device, or alternative sensors such as WiFi, Bluetooth, ultrasound, or other location technologies that would be readily be understood by a person of ordinary skill in the art. Once the location sensor returns a location, a list of nearby light sources and their corresponding identification codes is retrieved. These lights will become the “candidates.” Any identification code detected by the mobile device's 103 image sensor will be compared against this list of candidate lights in order to determine the device's location. This process happens every time the mobile device 103 detects a major location change.
- FIG. 56 presents an algorithm for resolving between multiple light identifiers.
- Acquire Candidates 5601 fetches a list of nearby light identifiers. The list of nearby identifiers becomes the candidates new light identifiers will be compared to.
- Examine recent identifiers 5602 looks at the list of light identifiers that the mobile device 103 has recently seen.
- Determine distance from candidate 5603 then computes the distance between the current recently seen identifier and the second most recently seen identifier. This distance is defined as the difference between the signals.
- the concept is quite similar to a Hamming Distance, which measures the minimum number of substitutions required to change one code-word to another. Each of these candidate distances are stored in a buffer 5604 .
- Analyze Candidate Set 5606 looks at the candidate signals, their distances, and then ascertains which candidate is most likely.
- a challenge when using a light based positioning system is determining whether or not a current signal contains the light identification signature.
- the present disclosure contains a quality score that measures the quality of the current detection.
- This quality score is analogous to a signal to noise ratio.
- a signal to noise ratio can be defined as the ratio of the power between a signal and the background noise. This can be measured in a number of ways, including taking the average power of each, the root mean square (RMS) of the respective powers, or the ratios in decibels.
- the present disclosure contains multiple methods for determining signal quality.
- the quality score can be defined as the ratio of magnitudes of peaks of the signal spectrum.
- An algorithm first checks that all peaks of the spectrum are above a specified threshold, and then measures the ratio of the highest peak to the second highest peak.
- Another component of the quality score can be the distance of the peaks from the expected location of the peaks. For example, if a mobile device 103 were demodulating a DPR signal that was known to use the frequencies 1000 Hz, 1100 Hz, and 1200 Hz, and the receiver detected a signal of 800 Hz, the mobile device receiver's quality score would take into account the 200 Hz difference between the detected frequency 800 Hz and the closest known frequency of 1000 Hz.
- quality score determination also can be performed using pattern recognition algorithms.
- Pattern recognition algorithms are concerned with providing a label for a given set of data. Such algorithms output a confidence score associated with their choice, which can be used as the quality metric. If the quality metric/confidence score is too low, then the algorithm flags the result as not containing a signal. In the context of a light positioning system, this refers to a situation where the output of the demodulation algorithm is ignored.
- techniques for pattern recognition including neural networks, Bayes classifiers, kernel estimation, regression, principal component analysis, Kalman filters, or other such algorithms that would be readily understood by a person of ordinary skill in the art.
- a lighting control system In a variety of use cases, it is desirable to control certain aspects such as the brightness, color, schedule, or direction of a light.
- lighting control There are a number of technologies for lighting control, including both wireless systems such as Zigbee, WiFi, and 6LowPan, as well as wired technologies such as DMX or other standard lighting control protocols.
- wireless systems such as Zigbee, WiFi, and 6LowPan
- wired technologies such as DMX or other standard lighting control protocols.
- An important component of a lighting control system is the ability to know the physical locations of the lights such that they can be controlled.
- the central controller would need to know the locations of all lights within a building. Furthermore, a user might want to only control lights in their direct vicinity.
- a mobile device user 5803 is standing underneath DPR enabled lights 5802 b and 5802 c . Each light 5802 a - c is broadcasting a DPR modulated signal, which mobile device 5804 detects using its sensors. The mobile device then computes its indoor location, using the algorithms discussed previously. The mobile device user 5803 is granted permission to control the lights 5802 a - c around them.
- the mobile device user has a “lighting profile” that is associated with them. This lighting profile is used to adjust the lights in the room automatically, depending on the user's preferences.
- a common problem when configuring a lighting system is identifying the physical locations of lights for the purposes of lighting control.
- One step is network discovery, which is the problem of identifying devices on the lighting network.
- devices on the network may be connected through power line communication (PLC), Ethernet, fibre optics, or other wired communication as would be readily understood by one of ordinary skill in the art.
- PLC power line communication
- the light sources can be connected wirelessly using protocols such as WiFi, Zigbee, Bluetooth, 6LowPan, or other protocols that would be readily understood by a worker skilled in the art.
- the problem of network discovery is accounted for in the underlying protocol, during which each device within the network is assigned a unique identifier.
- the second step of configuring a networked lighting control system is determining the physical location of each light within the system.
- the present disclosure provides a method by which beacon based light sources broadcast a self-identifying pattern that is recognizable by a mobile device receiver. This self-identifying pattern can be used to assign the location of the light source when commissioning a light positioning system.
- the signal is demodulated using digital pulse recognition (DPR) techniques on an image sensor present on mobile device 5804 .
- DPR digital pulse recognition
- Mobile device user 5803 stands underneath light sources 5802 a - c .
- Each light source 5802 a - c is broadcasting DPR modulated signals, and is connected to a network 5801 .
- the lights be can networked using any standard networking technique.
- Mobile device user 5803 receives information through the light signals, they can use the received signals to commission the system.
- Mobile device user 5803 receives the light signals, and then assigns them a physical location within a building. The mobile device user can do the physical position assignment using a user interface like the one described in FIG. 48 , or via other inputs that would be readily available.
- a mobile device user 5803 For a networked lighting system, like the one presented in FIG. 58 , it is desirable to provide a mobile device user 5803 with the ability to control the lights both locally and remotely. If the lights are networked, the mobile device user 5803 could control the lights by selecting them manually via the user interface terminal. The lights could also adjust depending on the time of day, occupancy sensors, current energy prices, ambient light readings, or user preferences. Transmitting an identifier through a modulated light 5802 c , which could be modulated using DPR modulation, to a mobile device 5804 , allows the mobile device user to directly control the light source. For example, consider the case where mobile device user 5803 is standing underneath light source 5802 c , receiving a light identifier for the light source.
- the mobile device user could then send the identifier to a lighting control module, along with a set of instructions to control the light source 5802 c .
- This set of instructions could include the color, brightness, light direction, time varying signal, on/off schedule or any other parameters of the light source that a user would control.
- the light identifier could either be the network identifier of the light source (for example, the IP address if the light source were controlled over TCP/IP), or an identifier that could be correlated with the light source through the lighting controller.
- Acquiring metrics for light sources is typically a very cumbersome process. In most cases, a person wishing to measure light source metrics needs a special handset equipped with a multitude of sensors. This reporting process is labor intensive, expensive, and limited in the amount of data that it can gather. Data about how a light source performs over time is of large interest to light source manufacturers, who want to track how their products perform outside of their internal test facilities.
- a bulb may want to report. These include total time on, age, color shift, temperature history, current fluctuations, voltage fluctuations, individual LED performance, barometric pressure readings, dimming statistics, color statistics, manufacturer origin, parts included within the bulb, network status, or other such information that could be connected to the light source.
- FIG. 46 presents a system by which a light source uses a light based communication channel to report information about itself.
- a processing unit 4602 interfaces with sensors 4603 . Possible sensors include temperature, color temperature, electrical, barometric, network, or any other sensor that could be added by one skilled in the art.
- the processing 4602 acquires readings from the sensors at regular intervals, and then broadcasts those readings through modulator 4607 .
- Modulator 4607 is responsible for modulating the light output of light source 103 .
- modulator 4607 is a DPR modulator, as described previously in FIG. 21 .
- Data 4602 is passed from sensors 4603 to processing unit 4602 , before being sent to Encoder 2102 .
- the packet structure could be determined either in the processing unit 4602 or the modulator 4607 .
- the packet in addition to the standard start bits, data bits, and error bits, there could also be metadata tags that indicate the type of information in the packet. For example, there could be a special header that would indicate that the packet contains information about bulb longevity.
- the header could contain the length of the bulb longevity portion, or the length could be set as a predetermined portion.
- the header could also include an identifier to indicate which packet was being transmitted in a series of packets. This can be used for situations in which multiple pieces of data are being transmitted in succession.
- the design of a packet is well understood by workers of ordinary skill in the art.
- the present disclosure includes a packet structure that contains an identifier for the light source, light source dimming information, longevity, temperature, and color temperature.
- a timestamp is added to the data by the mobile device receiver 103 .
- the receiver can either send the data to a remote server for storage, or store it locally.
- the receiver device 103 would store the light source information before transmitting the data to a server once a sufficient connection is formed. In this way, mobile device receivers can crowd source the collection of information about light source performance, without having to do manual surveying. This could be done in conjunction with light sources providing an indoor positioning service.
- FIG. 59 contains a depiction of a mobile device user 5901 standing underneath light sources 4401 a - c , each broadcasting a modulated light signal.
- the product code is uploaded to a remote server along with its current position, which is derived using light positioning. This reduces the manual labor required on the part of the mobile device user.
- the product code could be a bar code, QR code, product photo, RF-ID, photo, or any other tag that would be readily understood by a person skilled in the art.
- CMOS complementary metal-oxide-semiconductor
- CCD charge coupled device
- the photodiode would be sampled by an analog to digital converter and then sent to a processing unit. In all of these cases, the only aspect that changes is the response function of the receiving device.
- One of ordinary skill in the art would readily understand the requirements to support DPR demodulation on alternative receivers, including but not limited to photodiodes and global shutter image sensors.
- FIG. 60 describes a physical DPR enclosure 6001 which contains the DPR modulator 6004 and stress relieved 6003 a - b incoming connections 6002 and outgoing connections 6005 .
- FIG. 61 depicts a Self-Identifying Optical Transmitter 6101 in accordance with some embodiments, which transmits an identifier via an optical signal.
- the Self-Identifying Optical Transmitter 6101 may also transmit additional data using the optical signal.
- Processing Unit 6104 sends a signal to modulator 6105 .
- Processor Unit 6104 can come in the form of a microcontroller, FPGA, series of logic gates, or other such computing element that would be readily understood by a person of ordinary skill in the art.
- the processing unit can also be a series of logic elements/switches controlled via analog circuitry. To minimize power consumption, the processing unit can be configured to operate in a low power state. Minimizing power consumption can be important in the case of a battery-powered system.
- the Self-Identifying Optical Transmitter 6101 receives power from Power Source 6103 .
- Power Source 6103 is a battery-powered system.
- Power Source 6103 can also be in the form of an external power source.
- the Processing Unit 6104 contains a Data Interface 6109 , which can be used to program the device, exchange data, or load information to be transmitted across Light Output 6110 .
- An executable program for Processing Unit 6104 may be pre-loaded before the Self-Identifying Optical Transmitter 6101 is deployed. This program may be in the form of one or more software modules.
- the processing unit contains a non-volatile memory storage area 6102 for storing information to be transmitted across the Light Output 6110 . This information can include an identifier for the Light Output 6110 .
- the identifier can be a quasi-unique identifier, or globally unique if the identifiers were centrally-managed or pre-configured. This quasi-unique random identifier is received on the mobile device, which then verifies that the mobile device came into close proximity with the self-identifying one-way optical transmitter.
- the data transmission may include data in addition to the identifier, such as meta-data.
- the optical data transmission stream can include information about the current battery state of the device. This information can be used to inform the owner of the device that it is time to change the battery.
- Modulator 6105 is used to control the power transmitted through the light source, thus driving the optically encoded signal in Light Output 6110 .
- Modulator 6105 can come in the form of a MOSFET, BJT, transistor switch, discharge circuit, or any such device for controlling current/voltage that would be understood by a person of ordinary skill in the art.
- Light source 6106 may take an electrical input from modulator 6105 and convert it into an optical signal.
- light source 6106 may include light emitting diodes (LEDs). LEDs may be current-driven devices, in which case the brightness of the LED is proportional to the current being driven through it. In other embodiments, the LEDs may be voltage-controlled, or other light sources aside from LEDs may be used that have different current/voltage characteristics. The light sources pulse the electrical signal received from the modulator in an optical format.
- LEDs light emitting diodes
- LEDs may be current-driven devices, in which case the brightness of the LED is proportional to the current being driven through it.
- the LEDs may be voltage-controlled, or other light sources aside from LEDs may be used that have different current/voltage characteristics.
- the light sources pulse the electrical signal received from the modulator in an optical format.
- Optics 6108 disperse the optical signal 6107 emitted from the light source 6106 to improve the ability of a mobile device 6203 , as represented in FIG. 62 , to receive and interpret the Light Output 6110 .
- the optical signal 6107 may be emitted from a single point source. Because it is desirable to allow a mobile device user to quickly scan their mobile device past the self-identifying optical transmitter, increasing the surface area of the optical signal may helpfully reduce the time used by a mobile device user to align their mobile device with the light source 6106 .
- mobile devices 6203 can come in many different form factors, it is desirable to have a wide surface area in order to support many different mobile devices. Dispersing the optical signal also reduces the likelihood that the brightness of individual point LED sources will wash out the image sensor on mobile device receiver 6203 . Furthermore, viewing an LED with the naked eye without dispersing the light may annoy users.
- FIG. 62 represents the use of self-identifying optical transmitters by museum patrons in a museum space, in accordance with some embodiments.
- This representation includes a museum space 6205 , museum patrons 6201 and 6204 , mobile device 6203 held by museum patron 6204 , and self-identifying one-way optical transmitters 6202 a - 6202 d .
- museum patrons 6201 and 6204 equipped with mobile devices browse a museum space 6205 and may desire additional information about the exhibits of the space.
- Self-identifying one-way optical transmitters 6202 a - 6202 d may be positioned throughout the exhibit 6205 .
- These transmitters may be strategically placed near points of particular interest, near points frequently visited by museum patrons, near points that are easily accessible by users of mobile devices, or in any other configuration within a space.
- the self-identifying optical transmitters may be mounted or placed vertically, horizontally, or at any other angle within the space.
- the self-identifying optical transmitters may be mounted or placed on walls, pedestals, displays, ceilings, or any other place visible by users of mobile devices.
- Self-identifying optical transmitters may also be positioned in other types of spaces, such as grocery stores, shopping malls, or transit stations. One or many self-identifying optical transmitters may be placed in these sites.
- museum patron and mobile device user 6204 may tap their mobile device 6203 onto the self-identifying one-way optical transmitter 6202 d .
- the museum patron may do this because he or she desires more information about the portion of the museum space in which he or she is located, because he or she wishes to report an error about the space, or for any other reason.
- This self-identifying one-way optical transmitter 6202 d is mounted on a wall within the museum space 6205 , and the light output from the transmitter may be received by an image sensor of the mobile device 6203 .
- a user does not necessarily need to tap their mobile device onto one of the self-identifying optical transmitters, but instead may place their mobile device in any position where it is able to receive the light output from a self-identifying optical transmitter.
- the mobile device 6203 may interpret the light output as a code. This code can be used to pull up additional content associated with the current location of self-identifying optical transmitter 6202 d within the museum space 6205 . In the case of a retail store, the code may be used to depict an advertisement, acquire a coupon, receive credit for visiting a location, order an item, call for customer service, or pull up an online order form. Any other information by be received and interpreted by the mobile device 6203 and then related to the location of the mobile device 6203 .
- a mobile device user 6201 or 6204 may use the self-identifying optical transmitters 6202 a - 6202 d to assign content to a particular location. For example, a common scenario when taking photographs is to tag the photograph to a particular physical location.
- the EXIF format which defines meta-data tags that are added to images, specifically builds in a standard set of tags for location information. These tags are commonly added when taking photographs with a GPS enabled mobile device.
- a mobile device user can utilize, for example, the self-identifying transmitter 6202 a to geo-tag media, in the same way that GPS is used to geo-tag a picture.
- geo-tag refers to associating a piece of digital media with a particular location. This location can be derived by the self-identifying transmitter, or by using position derived from light as described above.
- this user may first tap their mobile device onto self-identifying transmitter 6202 a and thus associate that picture with the transmitter 6202 a . The picture can then be uploaded to a remote server, with the corresponding identifier used to associate the picture with the self-identifying transmitter 6202 a .
- the geo-tagging information may be derived from an overhead light positioning system, such as the one described previously in U.S. patent application Ser. No. 13/526,773 filed Jun. 19, 2012 entitled “Method and System For Digital Pulse Recognition Demodulation.”
- the media is not necessarily limited to photos, but can take the form of audio recordings, movies, video, user generated text, or any such media that can be generated.
- FIG. 63 is a representation of a self-identifying optical transmitter 6301 .
- the transmitter includes light sources 6303 a and 6303 b that emit light towards a surface 6302 .
- the self-identifying optical transmitter 6301 may be placed in a museum, a retail store, or any other location where the optical signal emitted by the light sources may be accessible by a mobile device user.
- FIG. 63 depicts one embodiment of a self-identifying optical transmitter, a variety of housing shapes, material types, and light source placements may be used for altering or improving the optical performance of the self-identifying optical transmitter 6301 .
- a different number of light sources may also be used.
- the light sources may be LED point sources.
- the light sources may be are reflected off of a surface 6302 . Reflecting the light from the light sources in this way may increase the area across which the light may be received.
- the surface is ideally colored white, but can be any color that sufficiently reflects the light from light sources 6303 a and 6303 b .
- the light sources 6303 a and 6303 b can also have lensing on them in order to disperse the optical signal they emit. The lensing may be placed directly over the light sources, or on some other portion of the self-identifying optical transmitter. For example, in the case of a red light source being used, the surface can be colored in a different way in order to increase the reflectiveness.
- the surface 6202 can be angled, flat, rounded, or another such shape that would be understood by a person of ordinary skill in the art.
- a lens may be placed at an angle to surface 6202 such that the light sources are enclosed within the self-identifying optical transmitter and the lens.
- FIG. 64 is another representation of a self-identifying optical transmitter 6401 , according to some embodiments.
- the self-identifying optical transmitter 6401 may contain one or more light sources (not shown) and be enclosed by lensing 6402 to disperse the light from the light sources.
- a mobile device user may place their mobile device near the self-identifying optical transmitter 6401 or tap their mobile device onto the lensing 6402 itself.
- the shape of the lens may be round, flat, or any other shape that disperses the light source. Frosted lenses are a popular and effective choice for light dispersion, but any lens may be used.
- lensing can be combined with a reflective surface within the self-identifying optical transmitter 6401 to improve the signal dispersion characteristics even further.
- the top of the lens 6402 may be covered with a film or partially transparent surface to further improve optical dispersion.
- FIG. 65 depicts a self-identifying optical transmitter 6501 with a rounded lens 6502 , in accordance with some embodiments.
- the self-identifying optical transmitter 6501 may contain on or more light sources and a user may place their mobile device or near the transmitter to receive an optical signal broadcast from the light sources.
- the rounded lens can be of any dimension.
- a rounded lens holds advantages in terms of appearance and user experience. Since the rounded lens is raised, it forms an easier surface onto which a user may tap their mobile device. This is because the flat form factor of a typical mobile device will rest tangential to the curved surface of the rounded lens, making it unlikely that the camera lens will rest directly on the surface of the lens. Some separation between the lens and the surface is desirable to avoid washing out the image sensor.
- FIG. 66 illustrates another possible implementation of a self-identifying optical transmitter 6601 , in accordance with some embodiments.
- the self-identifying optical transmitter 6601 includes four light sources 6602 a - 6602 d arranged inside of a housing. A different number of light sources may also be used.
- the light sources 6602 a - 6602 d may be LED light sources. These light sources project a signal within and around the transmitter device. Having multiple light sources may improve the optical power of the transmitter. Arranging the light source at different position and angles within the self-identifying optical transmitter may increases the range and areas within which the optical signals broadcast may be received by a mobile device. However, some embodiments with multiple light sources have the disadvantage of possibly lowering the battery life because more light sources may draw a higher current.
- Each light source 6602 a - d may contain individual lenses.
- conserveing power, and reducing the light output for aesthetic purposes, is a desired feature of a self-identifying broadcast light source.
- One way to achieve this is by having the Processing Unit 6104 operate in a low power state.
- Another method for improving the lifetime and power consumption of a stand-alone optical-transmitter is to power cycle the device when it is not being used.
- there are a number of ways to achieve this In some embodiments, there may be a proximity sensor on the transmitter device 6101 . This proximity sensor is responsible for powering up the transmitter device 6101 when a user comes close to it. This ensures that the transmitter broadcasts the optical signal when there is a user nearby to receive it.
- Other embodiments have a mechanical button or switch that the user taps to turn on the light.
- Other embodiments may include an inductive or capacitive circuit that is triggered upon contact with the mobile device 6101 . All of these possible external inputs can connect to the self-identifying optical transmitter 6101 through data interface 6109 .
- DPR modulation is used to modulate the light source 6106 to transmit the light output 6110 .
- DPR modulation pulses the light source with a light pattern.
- a mobile device receiver demodulates the signal by exploiting the rolling shutter mechanism on a CMOS image sensor. The receiver examines the incoming images for patterns encoded within the light pulses.
- changing color patterns can be used to transmit an identifier.
- the information may be encoded into a series of changing color patterns.
- a mobile device receiver 6203 can examine the pattern of color shifts and decode the corresponding identifier. Note in both embodiments that use DPR modulation and embodiments that use color modulation, the information transfer is not necessarily limited to the transmission of an identifier. Additional information can also be encoded into the series of light pulses. This can include the battery state of the transmitter, total time on, or data sent via Data Interface 6109 . Note that Data Interface 6109 can connect with any arbitrary data source.
- PWM pulse width modulation
- PWM pulse width modulation
- PWM is a desirable choice of modulating LED sources because it reduces color shift in the LEDs. Because the color-shift of an LED changes depending on the amount of current that is driven through it, it is desirable to transmit a fixed current through the LEDs, and control the brightness by varying the time the LED is “on.” For this reason, many LED light sources use PWM dimming techniques, as opposed to constant current techniques that can cause color shift. By using PWM to construct an arbitrary waveform, information transfer can be facilitated across an optical channel while preserving the color quality of the LED output.
- PWM modulation is used to transmit an arbitrary signal by varying the duty cycle of a pulse at a set frequency. The width of the pulse represents a quantization of the amplitude of the arbitrary signal at a point in time.
- the carrier frequency is the frequency of the PWM wave.
- the choice of carrier frequency depends on a number of factors. These include the quantization resolution of the transmitter, the clock speed of the transmitter, and the sampling rate of the receiver.
- FIG. 67 illustrates an example waveform for using PWM to transmit an arbitrary signal. As discussed above, this can be used to drive an LED light source.
- a carrier wave 6703 representing a PWM wave with a set frequency, is used to represent an arbitrary signal 6702 .
- the width of the pulse 6701 is used to represent the amplitude of the signal 6702 .
- the PWM wave may act as an analog-to-digital converter for an arbitrary signal. For example, consider the waveform presented in FIG. 67 .
- the PWM carrier wave has a frequency of 64 Khz.
- the period of the wave is 1/64 Khz, or 15.6 microseconds.
- the amplitude of the signal is converted to a corresponding pulse width. So if the amplitude of the signal is 50% of its max value, the pulse width may be 50%. With a 64 Khz wave, this corresponds to a pulse width of 7.8 microseconds. If the amplitude is 25% of its max value, the pulse width may be 25%, or 3.9 microseconds.
- an analog signal is converted to a digital representation as a pulse width. Provided that the carrier frequency is chosen to be lower than the Nyquist rate of the mobile device receiver, any arbitrary signal can be transmitted to the mobile device.
- this PWM wave can be used to construct a sum of sinusoids.
- the combination of frequencies can then be mapped to an encoding scheme to uniquely identify a light source, or transmit other such data.
- Possible modulation techniques that can be constructed from PWM waves include Orthogonal Frequency-Division Multiplexing, Quadrature amplitude modulation, amplitude modulation, phase-shift keying, on-off keying, pulse-position modulation, spread spectrum, or other such modulation techniques that would be understood by a person of ordinary skill in the art.
- image sensor settings such as exposure, white balance, frame rate, and resolution may be modified in ways that improve the signal-to-noise characteristics of the receiver.
- increasing the frame rate of the receiver increases the sampling rate, and consequently the data rate of the receiver.
- increasing the resolution of the received image also improves the receiver capabilities. This is due to the discrete nature of the sampling process.
- increasing the resolution of the image sensor on a receiver effectively increases the number of samples.
- Increasing the number of samples when performing Fourier analysis may increase the frequency resolution of the Fourier transform.
- increasing the frequency resolution is important in increasing the number of identifiers that can be transmitted.
- Another benefit of increasing the frequency resolution is that, in some cases, this overrides optimizations done at the image sensor level. For example, a number of image sensors may compress an image before returning it to the higher layers of the software stack. Because this compression often happens at the driver level, some camera APIs may not be able to override the compression. Data compression can cause information within the image to be lost. In the case of a DPR modulated signal, this may cause the image to lose features that carry information transmitted via the optical signal.
- increasing the resolution of the image sensor 501 has the dual benefit of increasing the bandwidth of the receiver 103 , as well as reducing the possibility of information loss through compression and other optimizations at the image sensor level.
- Associating the media with the self-identifying transmitter, or a position derived from light allows for users to overlay digital content onto a physical space. Future visitors to the same location can scroll through the experiences of previous visitors to the space. Users watching remotely would be able to view a live feed of activity in the space, and see digital content as it is generated.
- a high-brightness light source 6801 is broadcasting a modulated signal overhead.
- the signal 6802 may be reflected off the clouds, or other large objects.
- Mobile device users, such as user 6804 can point their devices 6803 at the reflected signal 6802 , which is broadcasting an optical signal.
- Mobile device users can then upload text, status updates, audio, video, pictures, or other such media, which is tagged with the identifier received via the visible light signal.
- Remote users can then subscribe to a media feed that is tagged with the particular physical location.
- Users who view the cloud reflected signal 6802 can also be redirected to a web link, which can present them with advertisements, directions to a nearby restaurant, deals, additional information about a venue, a ticketing system, or other such data that would be understood by a person of ordinary skill in the art.
- a common usage scenario for one-way authentication systems is verifying that a user has visited a particular location. For example, consider the situation in FIG. 69 .
- Mobile device user 6902 is passing through a checkout aisle 6901 .
- the user may be participating in a customer loyalty program, where they receive a credit for walking through the checkout aisle.
- a mechanism may be used to tie the user's location to that particular location.
- the user 6902 may tap their mobile device 6904 onto a self-identifying optical transmitter 6903 placed near the point of interest. This transmitter 6903 transfers an identifier to the mobile 6904 , which stores the identifier to verify their position.
- This identifier can be used on an application running locally on the device, or transmitted to a remote server.
- the identifier provides a secure method by which the user's position may be verified. Combined with information about the user's identity, previous purchase history, demographics, and previous locations visited, the authenticated location transmission can be used to administer the customer loyalty program. Note that this approach has significant security advantages over QR codes, because it is very difficult to replicate the optical signal transmitted by transmitter 6903 .
Landscapes
- Engineering & Computer Science (AREA)
- Business, Economics & Management (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Strategic Management (AREA)
- Accounting & Taxation (AREA)
- Development Economics (AREA)
- Finance (AREA)
- Physics & Mathematics (AREA)
- Computer Security & Cryptography (AREA)
- Economics (AREA)
- Game Theory and Decision Science (AREA)
- Entrepreneurship & Innovation (AREA)
- Marketing (AREA)
- General Business, Economics & Management (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Electromagnetism (AREA)
- Optical Communication System (AREA)
Abstract
Description
Var(∠Y 0, . . . ,M−1 [k])→0,k=k BL
Var(∠Y 0, . . . ,M−1 [k])>>0,k≠k BL (1)
where k∈[klow,khigh] and klow and khigh denote the lowest and highest possible vertical frequencies of the periodic horizontal bands, respectively. Consequently, when kBL is unknown, it can be identified by determining which frequency component has minimal phase variance across all columns, i.e.
Phase Parameterization
P 0, . . . ,M−1 k=exp(j·∠Y 0, . . . ,M−1 [k]), (3)
where j is the imaginary unit. Subsequently, the variance in parameterized phase is given by
Var(p 0, . . . ,M−1 k)=E[(p 0, . . . ,M−1 k −E[p 0, . . . ,M−1 k])·
where E[X] denotes the expected value of X, and
respectively.
q dip=(q l +q r)/2 (7)
-
- a. qdip<1.5 (low dip quality)
- b. |F′[0, kcm]<0 (negative-valued filtered magnitude)
- c. |kcp−kcm|>2 (significant disagreement between phase-based and magnitude-based candidate frequencies)
Apply Steps 3-5 to Ŷ′0, . . . ,M−1[k′] specifically for the frequency range k′a≤k′≤k′b.
Define the high-precision estimate of the banding frequency as
x a =r h(x f −x b)+x b
Repeat Identifiers
Claims (20)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/951,446 US10291321B2 (en) | 2011-07-26 | 2018-04-12 | Self-identifying one-way authentication method using optical signals |
US16/367,866 US10484092B2 (en) | 2011-07-26 | 2019-03-28 | Modulating a light source in a light based positioning system with applied DC bias |
Applications Claiming Priority (20)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201161511589P | 2011-07-26 | 2011-07-26 | |
US201161567484P | 2011-12-06 | 2011-12-06 | |
US13/369,144 US9287976B2 (en) | 2011-07-26 | 2012-02-08 | Independent beacon based light position system |
US13/369,147 US8964016B2 (en) | 2011-07-26 | 2012-02-08 | Content delivery based on a light positioning system |
US13/422,580 US8248467B1 (en) | 2011-07-26 | 2012-03-16 | Light positioning system using digital pulse recognition |
US13/422,591 US8866391B2 (en) | 2011-07-26 | 2012-03-16 | Self identifying modulated light source |
US13/435,448 US20130030747A1 (en) | 2011-07-26 | 2012-03-30 | Method and system for calibrating a light based positioning system |
US13/445,019 US20130026941A1 (en) | 2011-07-26 | 2012-04-12 | Single wavelength light source for use in light based positioning system |
US13/446,506 US8994799B2 (en) | 2011-07-26 | 2012-04-13 | Method and system for determining the position of a device in a light based positioning system using locally stored maps |
US13/446,520 US8947513B2 (en) | 2011-07-26 | 2012-04-13 | Method and system for tracking and analyzing data obtained using a light based positioning system |
US201261635413P | 2012-04-19 | 2012-04-19 | |
US201261639428P | 2012-04-27 | 2012-04-27 | |
US13/526,656 US8334898B1 (en) | 2011-07-26 | 2012-06-19 | Method and system for configuring an imaging device for the reception of digital pulse recognition information |
US201261697098P | 2012-09-05 | 2012-09-05 | |
US201261715950P | 2012-10-19 | 2012-10-19 | |
US13/718,233 US9398190B2 (en) | 2011-07-26 | 2012-12-18 | Method and system for configuring an imaging device for the reception of digital pulse recognition information |
US14/019,376 US9288293B2 (en) | 2011-07-26 | 2013-09-05 | Method for hiding the camera preview view during position determination of a mobile device |
US14/058,678 US9444547B2 (en) | 2011-07-26 | 2013-10-21 | Self-identifying one-way authentication method using optical signals |
US15/136,275 US9973273B2 (en) | 2011-07-26 | 2016-04-22 | Self-indentifying one-way authentication method using optical signals |
US15/951,446 US10291321B2 (en) | 2011-07-26 | 2018-04-12 | Self-identifying one-way authentication method using optical signals |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/136,275 Continuation US9973273B2 (en) | 2011-07-26 | 2016-04-22 | Self-indentifying one-way authentication method using optical signals |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/367,866 Continuation US10484092B2 (en) | 2011-07-26 | 2019-03-28 | Modulating a light source in a light based positioning system with applied DC bias |
Publications (2)
Publication Number | Publication Date |
---|---|
US20180234182A1 US20180234182A1 (en) | 2018-08-16 |
US10291321B2 true US10291321B2 (en) | 2019-05-14 |
Family
ID=50343390
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/058,678 Active 2033-05-14 US9444547B2 (en) | 2011-07-26 | 2013-10-21 | Self-identifying one-way authentication method using optical signals |
US15/136,275 Active US9973273B2 (en) | 2011-07-26 | 2016-04-22 | Self-indentifying one-way authentication method using optical signals |
US15/951,446 Active US10291321B2 (en) | 2011-07-26 | 2018-04-12 | Self-identifying one-way authentication method using optical signals |
US16/367,866 Active US10484092B2 (en) | 2011-07-26 | 2019-03-28 | Modulating a light source in a light based positioning system with applied DC bias |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/058,678 Active 2033-05-14 US9444547B2 (en) | 2011-07-26 | 2013-10-21 | Self-identifying one-way authentication method using optical signals |
US15/136,275 Active US9973273B2 (en) | 2011-07-26 | 2016-04-22 | Self-indentifying one-way authentication method using optical signals |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/367,866 Active US10484092B2 (en) | 2011-07-26 | 2019-03-28 | Modulating a light source in a light based positioning system with applied DC bias |
Country Status (1)
Country | Link |
---|---|
US (4) | US9444547B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11381786B2 (en) * | 2018-11-23 | 2022-07-05 | Curtis Ray Robinson, JR. | Systems and methods for capturing images and video |
Families Citing this family (119)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9418115B2 (en) | 2011-07-26 | 2016-08-16 | Abl Ip Holding Llc | Location-based mobile services and applications |
US8416290B2 (en) | 2011-07-26 | 2013-04-09 | ByteLight, Inc. | Method and system for digital pulse recognition demodulation |
US9723676B2 (en) | 2011-07-26 | 2017-08-01 | Abl Ip Holding Llc | Method and system for modifying a beacon light source for use in a light based positioning system |
US8334898B1 (en) | 2011-07-26 | 2012-12-18 | ByteLight, Inc. | Method and system for configuring an imaging device for the reception of digital pulse recognition information |
US8248467B1 (en) | 2011-07-26 | 2012-08-21 | ByteLight, Inc. | Light positioning system using digital pulse recognition |
US9787397B2 (en) | 2011-07-26 | 2017-10-10 | Abl Ip Holding Llc | Self identifying modulated light source |
US9287976B2 (en) | 2011-07-26 | 2016-03-15 | Abl Ip Holding Llc | Independent beacon based light position system |
US9444547B2 (en) | 2011-07-26 | 2016-09-13 | Abl Ip Holding Llc | Self-identifying one-way authentication method using optical signals |
US8994799B2 (en) | 2011-07-26 | 2015-03-31 | ByteLight, Inc. | Method and system for determining the position of a device in a light based positioning system using locally stored maps |
WO2013074065A1 (en) | 2011-11-14 | 2013-05-23 | Intel Corporation | Methods and arrangements for frequency shift communications by undersampling |
US8908914B2 (en) * | 2012-01-17 | 2014-12-09 | Maxlinear, Inc. | Method and system for map generation for location and navigation with user sharing/social networking |
US8861976B2 (en) * | 2012-06-29 | 2014-10-14 | Intel Corporation | Transmit and receive MIMO protocols for light array communications |
US9148250B2 (en) | 2012-06-30 | 2015-09-29 | Intel Corporation | Methods and arrangements for error correction in decoding data from an electromagnetic radiator |
US9178615B2 (en) | 2012-09-28 | 2015-11-03 | Intel Corporation | Multiphase sampling of modulated light with phase synchronization field |
US9218532B2 (en) | 2012-09-28 | 2015-12-22 | Intel Corporation | Light ID error detection and correction for light receiver position determination |
US9590728B2 (en) | 2012-09-29 | 2017-03-07 | Intel Corporation | Integrated photogrammetric light communications positioning and inertial navigation system positioning |
US8878669B2 (en) | 2013-01-31 | 2014-11-04 | KHN Solutions, Inc. | Method and system for monitoring intoxication |
US9788772B2 (en) | 2013-01-31 | 2017-10-17 | KHN Solutions, Inc. | Wearable system and method for monitoring intoxication |
US9192334B2 (en) | 2013-01-31 | 2015-11-24 | KHN Solutions, Inc. | Method and system for monitoring intoxication |
KR20140105967A (en) * | 2013-02-25 | 2014-09-03 | 삼성전자주식회사 | Lighting control system and controling method for the same |
KR20140105968A (en) * | 2013-02-25 | 2014-09-03 | 삼성전자주식회사 | Lighting control system and controling method for the same |
US9830588B2 (en) * | 2013-02-26 | 2017-11-28 | Digimarc Corporation | Methods and arrangements for smartphone payments |
US9171281B1 (en) | 2013-06-01 | 2015-10-27 | Thomas Francis | Techniques for filling orders |
US9705600B1 (en) | 2013-06-05 | 2017-07-11 | Abl Ip Holding Llc | Method and system for optical communication |
CN103825871B (en) * | 2013-07-31 | 2015-05-27 | 深圳光启创新技术有限公司 | Authentication system and emission terminal, reception terminal and authority authentication method thereof |
KR101511442B1 (en) * | 2013-10-28 | 2015-04-13 | 서울과학기술대학교 산학협력단 | LED-ID/RF communication smart device using camera and the method of LBS using the same |
EP3075106A4 (en) * | 2013-11-25 | 2017-06-14 | ABL IP Holding LLC | System and method for communication with a mobile device via a positioning system including rf communication devices and modulated beacon light sources |
US9240839B2 (en) * | 2014-01-07 | 2016-01-19 | Nokia Corporation | Transmitting data to a rolling shutter sensor array via a light emitter array |
US9250228B2 (en) * | 2014-01-22 | 2016-02-02 | KHN Solutions, Inc. | Method and system for remotely monitoring intoxication |
US20150215744A1 (en) * | 2014-01-30 | 2015-07-30 | General Electric Company | System and method for indoor positioning, navigation and location specific services |
US9311639B2 (en) | 2014-02-11 | 2016-04-12 | Digimarc Corporation | Methods, apparatus and arrangements for device to device communication |
KR20150101140A (en) * | 2014-02-26 | 2015-09-03 | 한국전자통신연구원 | Apparatus and method for controlling zigbee wireless lighting |
CN106465512A (en) * | 2014-03-28 | 2017-02-22 | 罗伯特·博世有限公司 | Configuring lighting electronics using database and mobile device |
US9479250B2 (en) * | 2014-05-30 | 2016-10-25 | Comcast Cable Communications, Llc | Light based location system |
CN104022823B (en) * | 2014-06-11 | 2016-08-31 | 北京智谷睿拓技术服务有限公司 | Position service method and equipment |
US10009100B2 (en) | 2014-06-18 | 2018-06-26 | Qualcomm Incorporated | Transmission of identifiers using visible light communication |
US20160012426A1 (en) | 2014-07-11 | 2016-01-14 | Google Inc. | Hands-free transactions with a challenge and response |
US20160012421A1 (en) | 2014-07-11 | 2016-01-14 | Google Inc. | Hands-free transactions using beacon identifiers |
US9735868B2 (en) * | 2014-07-23 | 2017-08-15 | Qualcomm Incorporated | Derivation of an identifier encoded in a visible light communication signal |
US9749782B2 (en) * | 2014-07-31 | 2017-08-29 | Qualcomm Incorporated | Light fixture commissioning using encoded light signals |
CN105450298B (en) * | 2014-08-22 | 2017-12-19 | 扬州艾笛森光电有限公司 | Multidirectional optical positioning method and its device |
US9554100B2 (en) | 2014-09-30 | 2017-01-24 | Qualcomm Incorporated | Low-power always-on face detection, tracking, recognition and/or analysis using events-based vision sensor |
US9838635B2 (en) | 2014-09-30 | 2017-12-05 | Qualcomm Incorporated | Feature computation in a sensor element array |
US9940533B2 (en) | 2014-09-30 | 2018-04-10 | Qualcomm Incorporated | Scanning window for isolating pixel values in hardware for computer vision operations |
US20170132466A1 (en) | 2014-09-30 | 2017-05-11 | Qualcomm Incorporated | Low-power iris scan initialization |
US10515284B2 (en) | 2014-09-30 | 2019-12-24 | Qualcomm Incorporated | Single-processor computer vision hardware control and application execution |
CN104410603B (en) * | 2014-10-20 | 2018-02-13 | 北京数字天域科技有限责任公司 | A kind of method, apparatus and system for verifying terminal identity |
EP3220558B1 (en) * | 2014-11-14 | 2019-03-06 | Panasonic Intellectual Property Corporation of America | Reproduction method, reproduction device and program |
US20160173200A1 (en) * | 2014-12-16 | 2016-06-16 | AKT IP Ventures LLC | Multi-channel visible light communications systems and methods |
DE102015200214A1 (en) * | 2015-01-09 | 2016-07-14 | Siemens Healthcare Gmbh | Method for communication in a magnetic resonance device and magnetic resonance device |
CN104868951A (en) * | 2015-01-20 | 2015-08-26 | 深圳市裕富照明有限公司 | LED illumination-based visible light communication transmission method and system |
US9832338B2 (en) | 2015-03-06 | 2017-11-28 | Intel Corporation | Conveyance of hidden image data between output panel and digital camera |
DE102015205220A1 (en) * | 2015-03-23 | 2016-09-29 | Osram Gmbh | Tracking system and method for tracking a carrier of a mobile communication unit |
DE102015208002A1 (en) * | 2015-04-30 | 2016-11-03 | Zumtobel Lighting Gmbh | Method and system for improving a lighting control and method and system for controlling a lighting device |
WO2016186539A1 (en) | 2015-05-19 | 2016-11-24 | Telefonaktiebolaget Lm Ericsson (Publ) | A communications system, a station, a controller of a light source, and methods therein for authenticating the station to access a network. |
GB2539387B (en) * | 2015-06-09 | 2021-04-14 | Oxford Metrics Plc | Motion capture system |
CA3080452C (en) | 2015-08-05 | 2024-01-02 | Lutron Technology Company Llc | Load control system responsive to the location of an occupant and/or mobile device |
US10250336B1 (en) * | 2015-09-14 | 2019-04-02 | Triad National Security, Llc | Optical identification beacon |
US10552894B2 (en) | 2015-10-26 | 2020-02-04 | Thomas Francis | Techniques for filling orders |
WO2017070836A1 (en) * | 2015-10-27 | 2017-05-04 | Guangdong Virtual Reality Technology Co., Ltd. | Apparatus, methods, and systems for tracking an optical object |
WO2017093416A1 (en) * | 2015-12-04 | 2017-06-08 | Philips Lighting Holding B.V. | A commissioning device for commissioning a new device into a system and a method thereof |
US10277793B2 (en) * | 2015-12-15 | 2019-04-30 | International Business Machines Corporation | Handling operational settings in a digital imaging system |
US10476975B2 (en) * | 2015-12-31 | 2019-11-12 | Palantir Technologies Inc. | Building a user profile data repository |
CA3011000A1 (en) * | 2016-02-05 | 2017-08-10 | Schreder | Lamp control module consisting of base and control parts, communicating via nfc |
CN107086889A (en) * | 2016-02-16 | 2017-08-22 | 中兴通讯股份有限公司 | A kind of radio transmitting method, device and terminal |
CN108780477B (en) | 2016-03-01 | 2022-10-21 | 谷歌有限责任公司 | Facial profile modification for hands-free transactions |
US9949331B1 (en) | 2017-05-01 | 2018-04-17 | Gooee Limited | Automated luminaire identification and group assignment |
US10021758B2 (en) | 2016-03-11 | 2018-07-10 | Gooee Limited | Sensor board for luminaire/lighting system |
TWI584691B (en) * | 2016-03-31 | 2017-05-21 | 晶睿通訊股份有限公司 | Illuminating control system and method for controlling illuminating device |
WO2017184555A1 (en) * | 2016-04-19 | 2017-10-26 | Wal-Mart Stores, Inc. | Systems, apparatuses, and method for mapping a space |
CN105954719B (en) * | 2016-04-22 | 2019-03-19 | 深圳市摩仑科技有限公司 | A kind of low cost indoor orientation method and system |
US10054951B2 (en) * | 2016-05-25 | 2018-08-21 | Fuji Xerox Co., Ltd. | Mobile robot indoor localization and navigation system and method |
CN105898924A (en) * | 2016-05-30 | 2016-08-24 | 京东方科技集团股份有限公司 | Fresh food lamp, mobile terminal, product information determination system and determination method |
US10084979B2 (en) | 2016-07-29 | 2018-09-25 | International Business Machines Corporation | Camera apparatus and system, method and recording medium for indicating camera field of view |
JP6907315B2 (en) | 2016-07-31 | 2021-07-21 | グーグル エルエルシーGoogle LLC | Automatic hands-free service request |
CN109496187B (en) * | 2016-08-08 | 2022-07-26 | 金泰克斯公司 | System and method for processing video data to detect and eliminate flicker light source through dynamic exposure control |
CN107800418A (en) * | 2016-08-31 | 2018-03-13 | 赵锦薇 | Intelligent switch with remote control function |
US10650621B1 (en) | 2016-09-13 | 2020-05-12 | Iocurrents, Inc. | Interfacing with a vehicular controller area network |
US9939275B1 (en) * | 2016-09-25 | 2018-04-10 | Jawad A. Salehi | Methods and systems for geometrical optics positioning using spatial color coded LEDs |
US10984235B2 (en) | 2016-12-16 | 2021-04-20 | Qualcomm Incorporated | Low power data generation for iris-related detection and authentication |
US10614332B2 (en) | 2016-12-16 | 2020-04-07 | Qualcomm Incorportaed | Light source modulation for iris size adjustment |
US10142017B1 (en) | 2016-12-22 | 2018-11-27 | X Development Llc | Beacon demodulation with background subtraction |
CA3052420A1 (en) * | 2017-02-08 | 2018-08-16 | Eldolab Holding B.V. | Led driver for vlc |
DE102017206923B4 (en) * | 2017-04-25 | 2020-12-31 | Robert Bosch Gmbh | Controlling a directional light source |
CN107194448A (en) * | 2017-04-28 | 2017-09-22 | 南京邮电大学 | A kind of transmission and localization method based on visible light hidden Quick Response Code |
US10045415B1 (en) | 2017-05-01 | 2018-08-07 | Gooee Limited | Automated luminaire location identification and group assignment using light based communication for commissioning a lighting control system |
US9980337B1 (en) | 2017-05-01 | 2018-05-22 | Gooee Limited | Automated luminaire location identification and group assignment using light based sectorized communication for commissioning a lighting control system |
US10122455B1 (en) | 2017-05-01 | 2018-11-06 | Gooee Limited | VLC/DLC Sectorized communication |
US9992838B1 (en) | 2017-05-01 | 2018-06-05 | Gooee Limited | Automated luminaire identification and group assignment devices, systems, and methods using dimming function |
JP6887116B2 (en) * | 2017-06-19 | 2021-06-16 | パナソニックIpマネジメント株式会社 | Light source modulation circuit and method, and projector device |
WO2019013023A1 (en) * | 2017-07-11 | 2019-01-17 | 大学共同利用機関法人情報・システム研究機構 | Information transmission system |
WO2019016024A1 (en) * | 2017-07-19 | 2019-01-24 | Philips Lighting Holding B.V. | Illumination system for communicating data |
US10242390B2 (en) | 2017-07-31 | 2019-03-26 | Bank Of America Corporation | Digital data processing system for controlling automated exchange zone systems |
GB201715876D0 (en) * | 2017-09-29 | 2017-11-15 | Univ Strathclyde | Wireless optical communication and imaging systems and methods |
NL2019673B1 (en) * | 2017-10-05 | 2019-04-15 | Eldolab Holding Bv | System and method for operating at least one LED unit of a lighting grid comprising a plurality of LED units |
US11258787B2 (en) * | 2017-10-06 | 2022-02-22 | The Boeing Company | Network request handling based on optically-transmitted codes |
US10470155B2 (en) | 2017-11-30 | 2019-11-05 | Abl Ip Holding Llc | Commissioning of an indoor positioning system using a secondary positioning system |
US10402988B2 (en) * | 2017-11-30 | 2019-09-03 | Guangdong Virtual Reality Technology Co., Ltd. | Image processing apparatuses and methods |
US12055618B2 (en) * | 2017-12-29 | 2024-08-06 | Sonitor Technologies As | Location determination system having rotating identifiers for distinguishing transmitters |
KR102351498B1 (en) * | 2018-01-09 | 2022-01-14 | 삼성전자주식회사 | Data processing method and electronic apparatus thereof |
CN108269087B (en) | 2018-01-12 | 2020-07-28 | 阿里巴巴集团控股有限公司 | Method and device for processing position information |
US11324449B2 (en) | 2018-03-22 | 2022-05-10 | KHN Solutions, Inc. | Method and system for transdermal alcohol monitoring |
WO2019183581A2 (en) | 2018-03-22 | 2019-09-26 | KHN Solutions, Inc. | Method and system for transdermal alcohol monitoring |
US11163031B1 (en) * | 2018-08-03 | 2021-11-02 | Synapse Wireless, Inc. | Mapping light location through a data modulated light output and real-time location information |
WO2020030463A1 (en) | 2018-08-07 | 2020-02-13 | Signify Holding B.V. | Method and controller for reducing the energy consumption of a lighting system |
US11558949B2 (en) * | 2018-10-26 | 2023-01-17 | Current Lighting Solutions, Llc | Identification of lighting fixtures for indoor positioning using color band code |
US11474987B1 (en) | 2018-11-15 | 2022-10-18 | Palantir Technologies Inc. | Image analysis interface |
IT201900006400A1 (en) * | 2019-04-26 | 2020-10-26 | Tci Telecomunicazioni Italia S R L | PROCEDURE AND LOCATION SYSTEM USING CODED LIGHT |
TWI740300B (en) * | 2019-12-11 | 2021-09-21 | 宏碁股份有限公司 | Data transmission system and method |
JP2021101264A (en) * | 2019-12-24 | 2021-07-08 | 東芝テック株式会社 | Maintenance terminal and information processor |
CN113347313A (en) * | 2020-02-18 | 2021-09-03 | 宏碁股份有限公司 | Data transmission system and data transmission method |
US11153948B2 (en) * | 2020-03-02 | 2021-10-19 | Infineon Technologies Ag | Modular front light LED driver messaging system |
DE102020213286A1 (en) * | 2020-10-21 | 2022-04-21 | Robert Bosch Gesellschaft mit beschränkter Haftung | Method for determining a phase position of a yaw rate signal or a quadrature signal, method for adapting a demodulation phase and yaw rate sensor |
US11825574B2 (en) | 2020-12-29 | 2023-11-21 | Crestron Electronics, Inc. | System and method of commissioning a building control system |
US11602306B2 (en) | 2021-01-12 | 2023-03-14 | KHN Solutions, Inc. | Method and system for remote transdermal alcohol monitoring |
CN113381811A (en) * | 2021-04-14 | 2021-09-10 | 西安理工大学 | Method for safely transmitting information by adopting wireless laser |
US11553570B1 (en) | 2021-10-29 | 2023-01-10 | Infineon Technologies Ag | Interface expander circuit for light emitting diode (LED) driver circuits |
US11475110B1 (en) | 2022-03-04 | 2022-10-18 | Fmr Llc | Secure transmission and authentication of a user credential |
EP4304301A1 (en) * | 2022-07-06 | 2024-01-10 | Tridonic Portugal, Unipessoal Lda | Control and commissioning devices for verification of a commissioned lighting system, and system comprising said devices |
Citations (169)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4275385A (en) | 1979-08-13 | 1981-06-23 | Bell Telephone Laboratories, Incorporated | Infrared personnel locator system |
US5148159A (en) | 1989-04-26 | 1992-09-15 | Stanley Electronics | Remote control system with teach/learn setting of identification code |
US5521345A (en) | 1994-09-30 | 1996-05-28 | Tokheim Corporation | Backlit membrane keypad |
US5712839A (en) | 1995-01-19 | 1998-01-27 | Ricoh Company, Ltd. | Laser light power control system having reflected light detector |
US6198230B1 (en) | 1998-04-15 | 2001-03-06 | Talking Lights | Dual-use electronic transceiver set for wireless data networks |
US20010035905A1 (en) | 2000-04-04 | 2001-11-01 | Eric Auffret | Device for video transmission between a camera and a control room |
WO2002025842A2 (en) | 2000-09-19 | 2002-03-28 | Color Kinetics Incorporated | Universal lighting network method and system |
US6400482B1 (en) | 1998-04-15 | 2002-06-04 | Talking Lights, Llc | Communication system |
US6426599B1 (en) | 1999-04-14 | 2002-07-30 | Talking Lights, Llc | Dual-use electronic transceiver set for wireless data networks |
US6450816B1 (en) | 1998-03-09 | 2002-09-17 | Oerlikon Contraves Ag | Identification system |
US6462692B1 (en) | 1998-01-27 | 2002-10-08 | Matsushita Electric Industrial Co., Ltd. | Digital-to-analog converter and digital-to-analog converting method |
US6495783B2 (en) | 1999-12-30 | 2002-12-17 | Itt Manufacturing Enterprises, Inc. | Push actuated electrical switch |
US6504633B1 (en) | 1998-04-15 | 2003-01-07 | Talking Lights | Analog and digital electronic receivers for dual-use wireless data networks |
US6539400B1 (en) | 1999-09-20 | 2003-03-25 | Ncr Corporation | Information gathering and personalization techniques |
US20030100313A1 (en) | 2001-11-28 | 2003-05-29 | Denso Corporation | Radio communication terminal and position specifying system |
US6590687B1 (en) | 1999-03-11 | 2003-07-08 | El Paso Natural Gas | Low power optically coupled serial data link |
US6608453B2 (en) | 1997-08-26 | 2003-08-19 | Color Kinetics Incorporated | Methods and apparatus for controlling devices in a networked lighting system |
US6614126B1 (en) | 2001-10-24 | 2003-09-02 | Rockwell Collins, Inc. | Integrated lighting and data communication apparatus |
US20040013314A1 (en) | 1997-11-13 | 2004-01-22 | Eliezer Peli | Wide-band image enhancement |
US6701092B2 (en) | 1996-03-29 | 2004-03-02 | Dominion Lasercom, Inc. | Laser based telecommunication network and router |
US6710818B1 (en) | 1999-10-08 | 2004-03-23 | Matsushita Electric Industrial Co., Ltd. | Illumination flicker detection apparatus, an illumination flicker compensation apparatus, and an ac line frequency detection apparatus, methods of detecting illumination flicker, compensating illumination flicker, and measuring ac line frequency |
EP1439649A1 (en) | 2001-10-23 | 2004-07-21 | Sony Corporation | Data communication system, data transmitter and data receiver |
US6794831B2 (en) | 1998-04-15 | 2004-09-21 | Talking Lights Llc | Non-flickering illumination based communication |
US20040204848A1 (en) | 2002-06-20 | 2004-10-14 | Shigeru Matsuo | Navigation apparatus for receiving delivered information |
US6807478B2 (en) | 2001-12-27 | 2004-10-19 | Koninklijke Philips Electronics N.V. | In-building navigation system |
US20040256211A1 (en) | 2003-06-23 | 2004-12-23 | Emi Stop Corp. | Resilient switch contact for a key switch device |
US6865347B2 (en) | 2001-01-05 | 2005-03-08 | Motorola, Inc. | Optically-based location system and method for determining a location at a structure |
US20050177423A1 (en) | 2004-02-06 | 2005-08-11 | Capital One Financial Corporation | System and method of using RFID devices to analyze customer traffic patterns in order to improve a merchant's layout |
US20050232642A1 (en) | 2002-04-19 | 2005-10-20 | Koninklijke Philips Electronics N.V. | Method and device to identify a periodic light source |
US6985744B2 (en) | 2001-05-10 | 2006-01-10 | Hitachi, Ltd. | Cellular phone and a base station thereof |
US20060038916A1 (en) | 2004-08-17 | 2006-02-23 | Dialog Semiconductor Gmbh | Intelligent light source with synchronization with a digital camera |
US20060045311A1 (en) | 2004-09-02 | 2006-03-02 | Giken Trastem Co., Ltd. | Moving-object height determining apparatus |
US20060056855A1 (en) | 2002-10-24 | 2006-03-16 | Masao Nakagawa | Illuminative light communication device |
US7016115B1 (en) | 1998-04-15 | 2006-03-21 | Talking Lights, Llc | Communication with non-flickering illumination |
US7022928B2 (en) | 2003-08-07 | 2006-04-04 | Matsushita Electric Industrial Co., Ltd. | Push-on switch |
US20060071614A1 (en) | 2002-12-19 | 2006-04-06 | Koninklijke Philips Electronics N.V. | Leds driver |
US20060071613A1 (en) | 2002-12-05 | 2006-04-06 | Jean-Louis Lovato | Electroluminescent diode lighting device comprising a communication device and installation comprising one such device |
US20060119287A1 (en) | 2004-12-06 | 2006-06-08 | Kurt Campbell | Apparatus, logic and method for emulating the lighting effect of a candle |
US20060157760A1 (en) | 2005-01-04 | 2006-07-20 | Sony Corporation | Imaging apparatus and imaging method |
US7123159B2 (en) | 2001-12-27 | 2006-10-17 | Koninklijke Philips Electronics N. V. | Position dependent information retrieval system |
EP1715704A1 (en) | 2004-02-02 | 2006-10-25 | Nakagawa Laboratories, Inc. | Position information communication apparatus |
US20060287113A1 (en) | 2005-05-19 | 2006-12-21 | Small David B | Lazer tag advanced |
US7230196B2 (en) | 2004-09-27 | 2007-06-12 | Citizen Electronics Co., Ltd. | Lighted switch device |
US20070139405A1 (en) | 2005-12-19 | 2007-06-21 | Sony Ericsson Mobile Communications Ab | Apparatus and method of automatically adjusting a display experiencing varying lighting conditions |
US7265307B2 (en) | 2004-11-09 | 2007-09-04 | Alps Electric Co., Ltd. | Illumination push switch unit |
WO2007110791A1 (en) | 2006-03-24 | 2007-10-04 | Philips Intellectual Property & Standards Gmbh | Target atmosphere technique for easy light management systems and atmosphere localisation / rfid-assisted sensor network |
US20070254694A1 (en) | 2004-02-02 | 2007-11-01 | Nakagawa Laboratories, Inc. | Camera-Equipped Cellular Terminal for Visible Light Communication |
US20080028013A1 (en) | 1996-11-01 | 2008-01-31 | Oki Electric Industry Co., Ltd. | Two-dimensional fast fourier transform calculation method and apparatus |
KR20080022298A (en) | 2006-09-06 | 2008-03-11 | 삼성전자주식회사 | Hand over system of illumination light communication and method therefor |
US20080077326A1 (en) | 2006-05-31 | 2008-03-27 | Funk Benjamin E | Method and System for Locating and Monitoring First Responders |
US7352972B2 (en) | 1997-01-02 | 2008-04-01 | Convergence Wireless, Inc. | Method and apparatus for the zonal transmission of data using building lighting fixtures |
US20080122786A1 (en) | 1997-08-22 | 2008-05-29 | Pryor Timothy R | Advanced video gaming methods for education and play using camera based inputs |
US20080131140A1 (en) | 2006-11-30 | 2008-06-05 | Samsung Electronics Co., Ltd. | Method for communication link connection using visible light communication |
US20080185969A1 (en) | 2005-04-22 | 2008-08-07 | Koninklijke Philips Electronics, N.V. | Illumination Control |
US20080205477A1 (en) | 2004-12-15 | 2008-08-28 | Nichia Corporation | Light emitting device |
US20080225779A1 (en) | 2006-10-09 | 2008-09-18 | Paul Bragiel | Location-based networking system and method |
JP2008224536A (en) | 2007-03-14 | 2008-09-25 | Toshiba Corp | Receiving device of visible light communication, and visible light navigation system |
US20080258641A1 (en) | 2004-10-22 | 2008-10-23 | Nakagawa Laboratories, Inc. | Power Supply For Semiconductor Light Emitting Device And Illuminating Device |
US7446671B2 (en) | 2002-12-19 | 2008-11-04 | Koninklijke Philips Electronics N.V. | Method of configuration a wireless-controlled lighting system |
US7446276B2 (en) | 2006-11-16 | 2008-11-04 | Metrologic Instruments, Inc. | Button actuation assembly |
US7449654B2 (en) | 2006-08-01 | 2008-11-11 | Hosiden Corporation | Lateral pushing type push switch |
US7471315B2 (en) | 2003-03-14 | 2008-12-30 | Aptina Imaging Corporation | Apparatus and method for detecting and compensating for illuminant intensity changes within an image |
US20090026978A1 (en) | 2006-02-23 | 2009-01-29 | Tir Technology Lp | System and method for light source identification |
US20090027134A1 (en) | 2007-07-24 | 2009-01-29 | Advantest Corporation | Waveform generator, waveform generating device, test apparatus, and machine readable medium storing a program threrof |
US20090040367A1 (en) | 2002-05-20 | 2009-02-12 | Radoslaw Romuald Zakrzewski | Method for detection and recognition of fog presence within an aircraft compartment using video images |
US20090045955A1 (en) | 2007-08-13 | 2009-02-19 | Wal-Mart Stores, Inc. | Rfid theft prevention system |
US20090051768A1 (en) | 2006-08-31 | 2009-02-26 | Dekeyser Paul | Loop Recording With Book Marking |
US20090085500A1 (en) | 2007-09-24 | 2009-04-02 | Integrated Illumination Systems, Inc. | Systems and methods for providing an oem level networked lighting system |
US20090102962A1 (en) | 2003-08-04 | 2009-04-23 | Casio Computer Co., Ltd. | Image sensing apparatus, image sensing method, and recording medium which records photographing method |
US7525059B2 (en) | 2006-06-08 | 2009-04-28 | Panasonic Corporation | Push switch |
US7547858B2 (en) | 2005-12-26 | 2009-06-16 | Omron Corporation | Push button switch |
US20090157309A1 (en) | 2007-12-18 | 2009-06-18 | Eun-Tae Won | Method for exchanging messages in a navigation system using visible light communications |
US20090171571A1 (en) * | 2007-12-31 | 2009-07-02 | Samsung Electronics Co., Ltd | Navigation system and method using visible light communication |
US20090174338A1 (en) | 2007-11-28 | 2009-07-09 | Texas Instruments Incorporated | Led drive circuit |
US20090190441A1 (en) | 2008-01-29 | 2009-07-30 | Nec (China) Co., Ltd. | Autonomous ultrasonic indoor tracking system |
US20090245788A1 (en) | 2002-02-01 | 2009-10-01 | Cubic Corporation | Integrated optical communication and range finding system and application thereof |
US20090269073A1 (en) | 2005-08-31 | 2009-10-29 | Kyocera Corporation | Transmitter apparatus and communication system |
US20090284366A1 (en) * | 2008-05-14 | 2009-11-19 | Sony Ericsson Mobile Communications Ab | System and method for determining positioning information via modulated light |
US20090310971A1 (en) | 2008-06-17 | 2009-12-17 | Samsung Electronics Co., Ltd. | Visible light communication method and system |
US20100006763A1 (en) | 2008-07-14 | 2010-01-14 | Icx Technologies Gmbh | Detector System with Positioning System |
US20100014136A1 (en) | 2006-09-01 | 2010-01-21 | Ralf Haussler | Holographic Projection System Using Micro-Mirrors for Light Modulation |
US20100035905A1 (en) | 2006-10-13 | 2010-02-11 | Thomas Schmidt | Hydrates of 2-chloro-5-[3,6-dihydro-3-methyl-2,6-dioxo-4-(trifluoromethyl)-1-(2H)-pyrimidinyl]-4-fluoro-N-[[methyl(1-methylethyl)amino]sulfonyl]benzamide |
US20100053342A1 (en) | 2008-09-04 | 2010-03-04 | Samsung Electronics Co. Ltd. | Image edit method and apparatus for mobile terminal |
US7683954B2 (en) | 2006-09-29 | 2010-03-23 | Brainvision Inc. | Solid-state image sensor |
US20100123810A1 (en) * | 2008-11-14 | 2010-05-20 | Ati Technologies Ulc | Flicker Detection Circuit for Imaging Sensors that Employ Rolling Shutters |
US7724301B2 (en) | 2006-11-27 | 2010-05-25 | Nokia Corporation | Determination of mechanical shutter exposure time |
US7738884B2 (en) | 2005-06-28 | 2010-06-15 | Microsoft Corporation | Positioning service utilizing existing radio base stations |
US20100151903A1 (en) | 2008-12-17 | 2010-06-17 | Sony Ericsson Mobile Communications Japan, Inc. | Mobile phone terminal with camera function and control method thereof |
US7741573B2 (en) | 2006-09-13 | 2010-06-22 | Panasonic Corporation | Push switch |
US20100156907A1 (en) | 2008-12-23 | 2010-06-24 | Microsoft Corporation | Display surface tracking |
US20100159943A1 (en) | 2008-12-18 | 2010-06-24 | Verizon Corporate Services Group, Inc. | Method and system for providing location-based information to a group of mobile user agents |
US20100171875A1 (en) | 2009-01-07 | 2010-07-08 | Hoya Corporation | Imager capturing an image with a rolling shutter |
US20100176732A1 (en) | 2007-06-18 | 2010-07-15 | Koninklijke Philips Electronics N.V. | Direction controllable lighting unit |
US20100208986A1 (en) | 2009-02-18 | 2010-08-19 | Wesley Kenneth Cobb | Adaptive update of background pixel thresholds using sudden illumination change detection |
US20100207544A1 (en) | 2007-04-30 | 2010-08-19 | Koninklijke Philips Electronics N.V. | Method and system for dependently controlling colour light sources |
US20100208236A1 (en) | 2007-08-01 | 2010-08-19 | Koninklijke Philips Electronics N.V. | Method for determining the position of an object in a structure |
US20100219774A1 (en) | 2009-02-27 | 2010-09-02 | Osram Gesellschaft Mit Beschraenkter Haftung | Method for dimming light sources, related device and computer program product |
US7796780B2 (en) | 2005-06-24 | 2010-09-14 | Objectvideo, Inc. | Target detection and tracking from overhead video streams |
US20100244726A1 (en) | 2008-12-07 | 2010-09-30 | Melanson John L | Primary-side based control of secondary-side current for a transformer |
US20100244746A1 (en) | 2007-12-04 | 2010-09-30 | Koninklijke Philips Electronics N.V. | Lighting system and remote control method therefor |
US20100250185A1 (en) | 2009-03-27 | 2010-09-30 | Qinetiq Limited | Method for detection of gravitational anomalies |
WO2010146519A1 (en) | 2009-06-19 | 2010-12-23 | Koninklijke Philips Electronics N.V. | Illumination system and method with improved snr |
US20100328940A1 (en) | 2009-06-30 | 2010-12-30 | Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. | Lens, led module and illumination apparatus utilizing the same |
US20100328490A1 (en) | 2009-06-26 | 2010-12-30 | Seiko Epson Corporation | Imaging control apparatus, imaging apparatus and imaging control method |
US20110026918A1 (en) | 2009-08-03 | 2011-02-03 | Electronics And Telecommunications Research Institute | Apparatus for visible light communication indicating communication quality using rgb color mixing and method thereof |
US20110032230A1 (en) | 2007-02-15 | 2011-02-10 | Pixart Imaging Inc | Control device and control method for image display |
US7912377B2 (en) | 2005-11-04 | 2011-03-22 | Panasonic Corporation | Visible light communication apparatus and visible light communication method |
US20110069962A1 (en) | 2009-09-18 | 2011-03-24 | Interdigital Patent Holdings, Inc. | Method and apparatus for dimming with rate control for visible light communications (vlc) |
US20110069951A1 (en) | 2009-09-19 | 2011-03-24 | Samsung Electronics Co., Ltd. | Apparatus and method for supporting mobility of a mobile terminal that performs visible light communication |
US20110105134A1 (en) | 2009-10-31 | 2011-05-05 | Samsung Electronics Co., Ltd. | Visible light communication method and apparatus |
US20110105069A1 (en) | 2009-05-04 | 2011-05-05 | Qualcomm Incorporated | Systems, methods and apparatus for facilitating discontinuous reception |
US20110115816A1 (en) | 2009-11-16 | 2011-05-19 | Alliance For Sustainable Energy, Llc. | Augmented reality building operations tool |
WO2011064332A1 (en) | 2009-11-27 | 2011-06-03 | Hochschule Bochum | A navigation system and method for navigation using location signals from light sources |
US20110135317A1 (en) | 2009-12-03 | 2011-06-09 | Samsung Electronics Co., Ltd. | Controlling brightness of light sources used for data transmission |
US20110137881A1 (en) | 2009-12-04 | 2011-06-09 | Tak Keung Cheng | Location-Based Searching |
US20110136536A1 (en) | 2009-12-03 | 2011-06-09 | Qualcomm Incorporated | Method and apparatus for distributed processing for wireless sensors |
US20110153201A1 (en) | 2009-12-23 | 2011-06-23 | Samsung Electronics Co., Ltd. | Indoor navigation method and system using illumination lamps |
US7970537B2 (en) | 2007-05-11 | 2011-06-28 | Samsung Electronics Co., Ltd | System and method for navigation using visible light communications |
US7973819B2 (en) | 2007-07-31 | 2011-07-05 | Kabushiki Kaisha Toshiba | Method and apparatus for determining the position of a moving object, by using visible light communication |
US20110176803A1 (en) | 2010-01-15 | 2011-07-21 | Samsung Electronics Co., Ltd. | System and method for indoor positioning using led lighting |
US20110191237A1 (en) | 2009-11-25 | 2011-08-04 | Patrick Faith | Information Access Device and Data Transfer |
US20110199017A1 (en) | 2010-02-15 | 2011-08-18 | Osram Gesellschaft Mit Beschraenkter Haftung | Circuit and method for driving a luminous means |
US20110222858A1 (en) | 2010-03-09 | 2011-09-15 | Kddi R&D Laboratories Inc. | Optical communication apparatus and optical communication method |
US20110229130A1 (en) | 2008-11-25 | 2011-09-22 | Atsuya Yokoi | Visible ray communication system, transmission apparatus, and signal transmission method |
US20110266959A1 (en) | 2010-04-06 | 2011-11-03 | Lutron Electronics Co., Inc. | Method of Striking a Lamp in an Electronic Dimming Ballast Circuit |
US20110298886A1 (en) | 2010-06-06 | 2011-12-08 | Apple, Inc. | Auto Exposure Techniques for Variable Lighting Conditions |
US20110299857A1 (en) | 2010-06-02 | 2011-12-08 | Sony Corporaton | Transmission device, transmission method, reception device, reception method, communication system, and communication method |
US20120019171A1 (en) | 2009-02-24 | 2012-01-26 | Allan Firhoj | System, method and portable controller for programming and calibration of a plurality of light source units for photo-reactive/curing applications |
US8107825B2 (en) | 2009-05-08 | 2012-01-31 | Samsung Electronics Co., Ltd. | Apparatus and method for support of dimming in visible light communication |
US8131154B2 (en) | 2008-03-28 | 2012-03-06 | Planners Land Co., Ltd. | Visible light communication apparatus |
US20120080944A1 (en) | 2006-03-28 | 2012-04-05 | Wireless Environment, Llc. | Grid Shifting System for a Lighting Circuit |
US20120093241A1 (en) | 2010-10-15 | 2012-04-19 | Ikanos Communications, Inc. | Dsl alien noise reduction |
US20120126909A1 (en) | 2010-11-18 | 2012-05-24 | Mccune Jr Earl W | Duty cycle translator methods and apparatus |
US8188878B2 (en) | 2000-11-15 | 2012-05-29 | Federal Law Enforcement Development Services, Inc. | LED light communication system |
US20120133815A1 (en) | 2010-06-08 | 2012-05-31 | Koji Nakanishi | Information display apparatus, display control integrated circuit, and display control method |
US8195054B2 (en) | 2008-11-26 | 2012-06-05 | Samsung Electronics Co., Ltd | Apparatus and method for transmitting and receiving an information symbol in a visible light communication system for color code modulation |
US20120155889A1 (en) | 2010-12-15 | 2012-06-21 | Electronics And Telecommunications Research Institute | Method and apparatus for transmitting and receiving data using visible light communication |
US8213801B2 (en) | 2009-01-07 | 2012-07-03 | Industrial Technology Research Institute | Light emitting device, light receiving device, data transmission system and data transmission method using the same |
WO2012093241A1 (en) | 2011-01-07 | 2012-07-12 | Toshiba Research Europe Limited | Localisation of electronic equipment |
US20120176038A1 (en) | 2011-01-10 | 2012-07-12 | Cheon Eun | Light emitting diode emitting device |
US8248467B1 (en) | 2011-07-26 | 2012-08-21 | ByteLight, Inc. | Light positioning system using digital pulse recognition |
WO2012127439A1 (en) | 2011-03-22 | 2012-09-27 | Koninklijke Philips Electronics N.V. | Light detection system and method |
US20120252495A1 (en) | 2011-01-11 | 2012-10-04 | Qualcomm Incorporated | Positioning system using light information |
US20120256697A1 (en) | 2011-04-07 | 2012-10-11 | Peter Singerl | System and Method for Generating a Pulse-width Modulated Signal |
US20120275795A1 (en) | 2011-04-26 | 2012-11-01 | The Boeing Company | System and method of wireless optical communication |
WO2012165800A2 (en) | 2011-05-27 | 2012-12-06 | Samsung Electronics Co., Ltd. | Apparatus and method for identifying location information by using visible light communication and gps |
US8334901B1 (en) | 2011-07-26 | 2012-12-18 | ByteLight, Inc. | Method and system for modulating a light source in a light based positioning system using a DC bias |
US8334898B1 (en) | 2011-07-26 | 2012-12-18 | ByteLight, Inc. | Method and system for configuring an imaging device for the reception of digital pulse recognition information |
US20120328302A1 (en) | 2011-06-23 | 2012-12-27 | Casio Computer Co., Ltd. | Information transmission system, information sending device, information receiving device, information transmission method, information sending method, information receiving method and program product |
US20130026224A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for determining the position of a device in a light based positioning system using locally stored maps |
US20130027576A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for digital pulse recognition demodulation |
US20130028612A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for modulating a beacon light source in a light based positioning system |
US20130028609A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for demodulating a digital pulse recognition signal in a light based positioning system using a fourier transform |
US20130026945A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for modifying a beacon light source for use in a light based positioning system |
US20130026942A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Device for dimming a beacon light source used in a light based positioning system |
US20130027528A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for video processing to determine digital pulse recognition tones |
US20130040380A1 (en) | 2010-01-26 | 2013-02-14 | University Of Georgia Research Foundation, Inc. | Biological optimization systems for enhancing photosynthetic efficiency and methods of use15 |
US8379107B2 (en) | 2009-12-31 | 2013-02-19 | Lite-On Semiconductor Corp. | Flicker detection method and image sensing device utilizing the same |
US20130094668A1 (en) | 2011-10-13 | 2013-04-18 | Jens Kristian Poulsen | Proximity sensing for user detection and automatic volume regulation with sensor interruption override |
US20130126713A1 (en) | 2011-11-04 | 2013-05-23 | The University Court Of The University Of Edinburgh | Communication apparatus and method |
US20130141554A1 (en) | 2011-07-26 | 2013-06-06 | Aaron Ganick | Independent beacon based light position system |
US8494218B2 (en) | 2009-08-18 | 2013-07-23 | Industrial Technology Research Institute | Light information receiving method, unit and method for recognition of light-emitting objects |
US20130293877A1 (en) | 2012-05-03 | 2013-11-07 | David P. Ramer | Lighting devices with sensors for detecting one or more external conditions and networked system using such devices |
US20130297212A1 (en) | 2012-05-03 | 2013-11-07 | David P. Ramer | Networked architecture for system of lighting devices having sensors, for intelligent applications |
US20140086590A1 (en) | 2011-07-26 | 2014-03-27 | ByteLight, Inc. | Self-identifying one-way authentication method using optical signals |
WO2014063150A2 (en) | 2012-10-19 | 2014-04-24 | Daniel Ryan | Self-identifying one-way authentication method using optical signals |
US8732031B2 (en) | 2012-06-12 | 2014-05-20 | Sensity Systems, Inc. | Lighting infrastructure and revenue model |
EP2737779A1 (en) | 2011-07-26 | 2014-06-04 | Bytelight, Inc. | Self identifying modulater light source |
US20150043425A1 (en) | 2013-08-12 | 2015-02-12 | Abl Ip Holding Llc | Lighting element-centric network of networks |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2188358A1 (en) * | 1996-10-21 | 1998-04-21 | Michael J. Sieben | optical modulation system |
US8964041B2 (en) * | 2011-04-07 | 2015-02-24 | Fr Vision Ab | System and method for video stabilization of rolling shutter cameras |
US9418115B2 (en) | 2011-07-26 | 2016-08-16 | Abl Ip Holding Llc | Location-based mobile services and applications |
EP3075106A4 (en) | 2013-11-25 | 2017-06-14 | ABL IP Holding LLC | System and method for communication with a mobile device via a positioning system including rf communication devices and modulated beacon light sources |
-
2013
- 2013-10-21 US US14/058,678 patent/US9444547B2/en active Active
-
2016
- 2016-04-22 US US15/136,275 patent/US9973273B2/en active Active
-
2018
- 2018-04-12 US US15/951,446 patent/US10291321B2/en active Active
-
2019
- 2019-03-28 US US16/367,866 patent/US10484092B2/en active Active
Patent Citations (199)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4275385A (en) | 1979-08-13 | 1981-06-23 | Bell Telephone Laboratories, Incorporated | Infrared personnel locator system |
US5148159A (en) | 1989-04-26 | 1992-09-15 | Stanley Electronics | Remote control system with teach/learn setting of identification code |
US5521345A (en) | 1994-09-30 | 1996-05-28 | Tokheim Corporation | Backlit membrane keypad |
US5712839A (en) | 1995-01-19 | 1998-01-27 | Ricoh Company, Ltd. | Laser light power control system having reflected light detector |
US6701092B2 (en) | 1996-03-29 | 2004-03-02 | Dominion Lasercom, Inc. | Laser based telecommunication network and router |
US20080028013A1 (en) | 1996-11-01 | 2008-01-31 | Oki Electric Industry Co., Ltd. | Two-dimensional fast fourier transform calculation method and apparatus |
US7352972B2 (en) | 1997-01-02 | 2008-04-01 | Convergence Wireless, Inc. | Method and apparatus for the zonal transmission of data using building lighting fixtures |
US20080122786A1 (en) | 1997-08-22 | 2008-05-29 | Pryor Timothy R | Advanced video gaming methods for education and play using camera based inputs |
US6548967B1 (en) | 1997-08-26 | 2003-04-15 | Color Kinetics, Inc. | Universal lighting network methods and systems |
US7309965B2 (en) | 1997-08-26 | 2007-12-18 | Color Kinetics Incorporated | Universal lighting network methods and systems |
US6608453B2 (en) | 1997-08-26 | 2003-08-19 | Color Kinetics Incorporated | Methods and apparatus for controlling devices in a networked lighting system |
US20040013314A1 (en) | 1997-11-13 | 2004-01-22 | Eliezer Peli | Wide-band image enhancement |
US6462692B1 (en) | 1998-01-27 | 2002-10-08 | Matsushita Electric Industrial Co., Ltd. | Digital-to-analog converter and digital-to-analog converting method |
US6450816B1 (en) | 1998-03-09 | 2002-09-17 | Oerlikon Contraves Ag | Identification system |
US6400482B1 (en) | 1998-04-15 | 2002-06-04 | Talking Lights, Llc | Communication system |
US6198230B1 (en) | 1998-04-15 | 2001-03-06 | Talking Lights | Dual-use electronic transceiver set for wireless data networks |
US6504633B1 (en) | 1998-04-15 | 2003-01-07 | Talking Lights | Analog and digital electronic receivers for dual-use wireless data networks |
US6954591B2 (en) | 1998-04-15 | 2005-10-11 | Lupton Elmer C | Non-visible communication systems |
US7016115B1 (en) | 1998-04-15 | 2006-03-21 | Talking Lights, Llc | Communication with non-flickering illumination |
US6794831B2 (en) | 1998-04-15 | 2004-09-21 | Talking Lights Llc | Non-flickering illumination based communication |
US6590687B1 (en) | 1999-03-11 | 2003-07-08 | El Paso Natural Gas | Low power optically coupled serial data link |
US6426599B1 (en) | 1999-04-14 | 2002-07-30 | Talking Lights, Llc | Dual-use electronic transceiver set for wireless data networks |
US6539400B1 (en) | 1999-09-20 | 2003-03-25 | Ncr Corporation | Information gathering and personalization techniques |
US6710818B1 (en) | 1999-10-08 | 2004-03-23 | Matsushita Electric Industrial Co., Ltd. | Illumination flicker detection apparatus, an illumination flicker compensation apparatus, and an ac line frequency detection apparatus, methods of detecting illumination flicker, compensating illumination flicker, and measuring ac line frequency |
US6495783B2 (en) | 1999-12-30 | 2002-12-17 | Itt Manufacturing Enterprises, Inc. | Push actuated electrical switch |
US20010035905A1 (en) | 2000-04-04 | 2001-11-01 | Eric Auffret | Device for video transmission between a camera and a control room |
WO2002025842A2 (en) | 2000-09-19 | 2002-03-28 | Color Kinetics Incorporated | Universal lighting network method and system |
US8188878B2 (en) | 2000-11-15 | 2012-05-29 | Federal Law Enforcement Development Services, Inc. | LED light communication system |
US6865347B2 (en) | 2001-01-05 | 2005-03-08 | Motorola, Inc. | Optically-based location system and method for determining a location at a structure |
US6985744B2 (en) | 2001-05-10 | 2006-01-10 | Hitachi, Ltd. | Cellular phone and a base station thereof |
US7415212B2 (en) | 2001-10-23 | 2008-08-19 | Sony Corporation | Data communication system, data transmitter and data receiver |
EP1439649A1 (en) | 2001-10-23 | 2004-07-21 | Sony Corporation | Data communication system, data transmitter and data receiver |
US6614126B1 (en) | 2001-10-24 | 2003-09-02 | Rockwell Collins, Inc. | Integrated lighting and data communication apparatus |
US20030100313A1 (en) | 2001-11-28 | 2003-05-29 | Denso Corporation | Radio communication terminal and position specifying system |
US6807478B2 (en) | 2001-12-27 | 2004-10-19 | Koninklijke Philips Electronics N.V. | In-building navigation system |
US7123159B2 (en) | 2001-12-27 | 2006-10-17 | Koninklijke Philips Electronics N. V. | Position dependent information retrieval system |
US20090245788A1 (en) | 2002-02-01 | 2009-10-01 | Cubic Corporation | Integrated optical communication and range finding system and application thereof |
US20050232642A1 (en) | 2002-04-19 | 2005-10-20 | Koninklijke Philips Electronics N.V. | Method and device to identify a periodic light source |
US20090040367A1 (en) | 2002-05-20 | 2009-02-12 | Radoslaw Romuald Zakrzewski | Method for detection and recognition of fog presence within an aircraft compartment using video images |
US20040204848A1 (en) | 2002-06-20 | 2004-10-14 | Shigeru Matsuo | Navigation apparatus for receiving delivered information |
US20060056855A1 (en) | 2002-10-24 | 2006-03-16 | Masao Nakagawa | Illuminative light communication device |
US7583901B2 (en) | 2002-10-24 | 2009-09-01 | Nakagawa Laboratories, Inc. | Illuminative light communication device |
US20060071613A1 (en) | 2002-12-05 | 2006-04-06 | Jean-Louis Lovato | Electroluminescent diode lighting device comprising a communication device and installation comprising one such device |
US20060071614A1 (en) | 2002-12-19 | 2006-04-06 | Koninklijke Philips Electronics N.V. | Leds driver |
US7446671B2 (en) | 2002-12-19 | 2008-11-04 | Koninklijke Philips Electronics N.V. | Method of configuration a wireless-controlled lighting system |
US7471315B2 (en) | 2003-03-14 | 2008-12-30 | Aptina Imaging Corporation | Apparatus and method for detecting and compensating for illuminant intensity changes within an image |
US20040256211A1 (en) | 2003-06-23 | 2004-12-23 | Emi Stop Corp. | Resilient switch contact for a key switch device |
US20090102962A1 (en) | 2003-08-04 | 2009-04-23 | Casio Computer Co., Ltd. | Image sensing apparatus, image sensing method, and recording medium which records photographing method |
US7022928B2 (en) | 2003-08-07 | 2006-04-04 | Matsushita Electric Industrial Co., Ltd. | Push-on switch |
US20070254694A1 (en) | 2004-02-02 | 2007-11-01 | Nakagawa Laboratories, Inc. | Camera-Equipped Cellular Terminal for Visible Light Communication |
US20070275750A1 (en) | 2004-02-02 | 2007-11-29 | Nakagawa Laboratories, Inc. | Position Data Communication Device |
EP1715704A1 (en) | 2004-02-02 | 2006-10-25 | Nakagawa Laboratories, Inc. | Position information communication apparatus |
US20050177423A1 (en) | 2004-02-06 | 2005-08-11 | Capital One Financial Corporation | System and method of using RFID devices to analyze customer traffic patterns in order to improve a merchant's layout |
US20060038916A1 (en) | 2004-08-17 | 2006-02-23 | Dialog Semiconductor Gmbh | Intelligent light source with synchronization with a digital camera |
US20060045311A1 (en) | 2004-09-02 | 2006-03-02 | Giken Trastem Co., Ltd. | Moving-object height determining apparatus |
US7230196B2 (en) | 2004-09-27 | 2007-06-12 | Citizen Electronics Co., Ltd. | Lighted switch device |
US20080258641A1 (en) | 2004-10-22 | 2008-10-23 | Nakagawa Laboratories, Inc. | Power Supply For Semiconductor Light Emitting Device And Illuminating Device |
US7265307B2 (en) | 2004-11-09 | 2007-09-04 | Alps Electric Co., Ltd. | Illumination push switch unit |
US20060119287A1 (en) | 2004-12-06 | 2006-06-08 | Kurt Campbell | Apparatus, logic and method for emulating the lighting effect of a candle |
US20080205477A1 (en) | 2004-12-15 | 2008-08-28 | Nichia Corporation | Light emitting device |
US20060157760A1 (en) | 2005-01-04 | 2006-07-20 | Sony Corporation | Imaging apparatus and imaging method |
US20080185969A1 (en) | 2005-04-22 | 2008-08-07 | Koninklijke Philips Electronics, N.V. | Illumination Control |
US20060287113A1 (en) | 2005-05-19 | 2006-12-21 | Small David B | Lazer tag advanced |
US7796780B2 (en) | 2005-06-24 | 2010-09-14 | Objectvideo, Inc. | Target detection and tracking from overhead video streams |
US7738884B2 (en) | 2005-06-28 | 2010-06-15 | Microsoft Corporation | Positioning service utilizing existing radio base stations |
US20090269073A1 (en) | 2005-08-31 | 2009-10-29 | Kyocera Corporation | Transmitter apparatus and communication system |
US7912377B2 (en) | 2005-11-04 | 2011-03-22 | Panasonic Corporation | Visible light communication apparatus and visible light communication method |
US20070139405A1 (en) | 2005-12-19 | 2007-06-21 | Sony Ericsson Mobile Communications Ab | Apparatus and method of automatically adjusting a display experiencing varying lighting conditions |
US7547858B2 (en) | 2005-12-26 | 2009-06-16 | Omron Corporation | Push button switch |
US20090026978A1 (en) | 2006-02-23 | 2009-01-29 | Tir Technology Lp | System and method for light source identification |
WO2007110791A1 (en) | 2006-03-24 | 2007-10-04 | Philips Intellectual Property & Standards Gmbh | Target atmosphere technique for easy light management systems and atmosphere localisation / rfid-assisted sensor network |
US20120080944A1 (en) | 2006-03-28 | 2012-04-05 | Wireless Environment, Llc. | Grid Shifting System for a Lighting Circuit |
US20080077326A1 (en) | 2006-05-31 | 2008-03-27 | Funk Benjamin E | Method and System for Locating and Monitoring First Responders |
US7525059B2 (en) | 2006-06-08 | 2009-04-28 | Panasonic Corporation | Push switch |
US7449654B2 (en) | 2006-08-01 | 2008-11-11 | Hosiden Corporation | Lateral pushing type push switch |
US20090051768A1 (en) | 2006-08-31 | 2009-02-26 | Dekeyser Paul | Loop Recording With Book Marking |
US20100014136A1 (en) | 2006-09-01 | 2010-01-21 | Ralf Haussler | Holographic Projection System Using Micro-Mirrors for Light Modulation |
KR20080022298A (en) | 2006-09-06 | 2008-03-11 | 삼성전자주식회사 | Hand over system of illumination light communication and method therefor |
US7741573B2 (en) | 2006-09-13 | 2010-06-22 | Panasonic Corporation | Push switch |
US7683954B2 (en) | 2006-09-29 | 2010-03-23 | Brainvision Inc. | Solid-state image sensor |
US20080225779A1 (en) | 2006-10-09 | 2008-09-18 | Paul Bragiel | Location-based networking system and method |
US20100035905A1 (en) | 2006-10-13 | 2010-02-11 | Thomas Schmidt | Hydrates of 2-chloro-5-[3,6-dihydro-3-methyl-2,6-dioxo-4-(trifluoromethyl)-1-(2H)-pyrimidinyl]-4-fluoro-N-[[methyl(1-methylethyl)amino]sulfonyl]benzamide |
US7446276B2 (en) | 2006-11-16 | 2008-11-04 | Metrologic Instruments, Inc. | Button actuation assembly |
US7724301B2 (en) | 2006-11-27 | 2010-05-25 | Nokia Corporation | Determination of mechanical shutter exposure time |
US20080131140A1 (en) | 2006-11-30 | 2008-06-05 | Samsung Electronics Co., Ltd. | Method for communication link connection using visible light communication |
US20110032230A1 (en) | 2007-02-15 | 2011-02-10 | Pixart Imaging Inc | Control device and control method for image display |
JP2008224536A (en) | 2007-03-14 | 2008-09-25 | Toshiba Corp | Receiving device of visible light communication, and visible light navigation system |
US20100207544A1 (en) | 2007-04-30 | 2010-08-19 | Koninklijke Philips Electronics N.V. | Method and system for dependently controlling colour light sources |
US7970537B2 (en) | 2007-05-11 | 2011-06-28 | Samsung Electronics Co., Ltd | System and method for navigation using visible light communications |
US20100176732A1 (en) | 2007-06-18 | 2010-07-15 | Koninklijke Philips Electronics N.V. | Direction controllable lighting unit |
US20090027134A1 (en) | 2007-07-24 | 2009-01-29 | Advantest Corporation | Waveform generator, waveform generating device, test apparatus, and machine readable medium storing a program threrof |
US7973819B2 (en) | 2007-07-31 | 2011-07-05 | Kabushiki Kaisha Toshiba | Method and apparatus for determining the position of a moving object, by using visible light communication |
US20100208236A1 (en) | 2007-08-01 | 2010-08-19 | Koninklijke Philips Electronics N.V. | Method for determining the position of an object in a structure |
US20090045955A1 (en) | 2007-08-13 | 2009-02-19 | Wal-Mart Stores, Inc. | Rfid theft prevention system |
US20090085500A1 (en) | 2007-09-24 | 2009-04-02 | Integrated Illumination Systems, Inc. | Systems and methods for providing an oem level networked lighting system |
US20090174338A1 (en) | 2007-11-28 | 2009-07-09 | Texas Instruments Incorporated | Led drive circuit |
US20100244746A1 (en) | 2007-12-04 | 2010-09-30 | Koninklijke Philips Electronics N.V. | Lighting system and remote control method therefor |
US20090157309A1 (en) | 2007-12-18 | 2009-06-18 | Eun-Tae Won | Method for exchanging messages in a navigation system using visible light communications |
US20090171571A1 (en) * | 2007-12-31 | 2009-07-02 | Samsung Electronics Co., Ltd | Navigation system and method using visible light communication |
US20090190441A1 (en) | 2008-01-29 | 2009-07-30 | Nec (China) Co., Ltd. | Autonomous ultrasonic indoor tracking system |
US8131154B2 (en) | 2008-03-28 | 2012-03-06 | Planners Land Co., Ltd. | Visible light communication apparatus |
US20090284366A1 (en) * | 2008-05-14 | 2009-11-19 | Sony Ericsson Mobile Communications Ab | System and method for determining positioning information via modulated light |
US7969297B2 (en) | 2008-05-14 | 2011-06-28 | Sony Ericsson Mobile Communications Ab | System and method for determining positioning information via modulated light |
US20090310971A1 (en) | 2008-06-17 | 2009-12-17 | Samsung Electronics Co., Ltd. | Visible light communication method and system |
US20100006763A1 (en) | 2008-07-14 | 2010-01-14 | Icx Technologies Gmbh | Detector System with Positioning System |
US20100053342A1 (en) | 2008-09-04 | 2010-03-04 | Samsung Electronics Co. Ltd. | Image edit method and apparatus for mobile terminal |
US20100123810A1 (en) * | 2008-11-14 | 2010-05-20 | Ati Technologies Ulc | Flicker Detection Circuit for Imaging Sensors that Employ Rolling Shutters |
US20110229130A1 (en) | 2008-11-25 | 2011-09-22 | Atsuya Yokoi | Visible ray communication system, transmission apparatus, and signal transmission method |
US8195054B2 (en) | 2008-11-26 | 2012-06-05 | Samsung Electronics Co., Ltd | Apparatus and method for transmitting and receiving an information symbol in a visible light communication system for color code modulation |
US20100244726A1 (en) | 2008-12-07 | 2010-09-30 | Melanson John L | Primary-side based control of secondary-side current for a transformer |
US20100151903A1 (en) | 2008-12-17 | 2010-06-17 | Sony Ericsson Mobile Communications Japan, Inc. | Mobile phone terminal with camera function and control method thereof |
US20100159943A1 (en) | 2008-12-18 | 2010-06-24 | Verizon Corporate Services Group, Inc. | Method and system for providing location-based information to a group of mobile user agents |
US20100156907A1 (en) | 2008-12-23 | 2010-06-24 | Microsoft Corporation | Display surface tracking |
US20100171875A1 (en) | 2009-01-07 | 2010-07-08 | Hoya Corporation | Imager capturing an image with a rolling shutter |
US8213801B2 (en) | 2009-01-07 | 2012-07-03 | Industrial Technology Research Institute | Light emitting device, light receiving device, data transmission system and data transmission method using the same |
US20100208986A1 (en) | 2009-02-18 | 2010-08-19 | Wesley Kenneth Cobb | Adaptive update of background pixel thresholds using sudden illumination change detection |
US20120019171A1 (en) | 2009-02-24 | 2012-01-26 | Allan Firhoj | System, method and portable controller for programming and calibration of a plurality of light source units for photo-reactive/curing applications |
US20100219774A1 (en) | 2009-02-27 | 2010-09-02 | Osram Gesellschaft Mit Beschraenkter Haftung | Method for dimming light sources, related device and computer program product |
US20100250185A1 (en) | 2009-03-27 | 2010-09-30 | Qinetiq Limited | Method for detection of gravitational anomalies |
US20110105069A1 (en) | 2009-05-04 | 2011-05-05 | Qualcomm Incorporated | Systems, methods and apparatus for facilitating discontinuous reception |
US8107825B2 (en) | 2009-05-08 | 2012-01-31 | Samsung Electronics Co., Ltd. | Apparatus and method for support of dimming in visible light communication |
EP2443911A1 (en) | 2009-06-19 | 2012-04-25 | Koninklijke Philips Electronics N.V. | Illumination system and method with improved snr |
WO2010146519A1 (en) | 2009-06-19 | 2010-12-23 | Koninklijke Philips Electronics N.V. | Illumination system and method with improved snr |
US20100328490A1 (en) | 2009-06-26 | 2010-12-30 | Seiko Epson Corporation | Imaging control apparatus, imaging apparatus and imaging control method |
US20100328940A1 (en) | 2009-06-30 | 2010-12-30 | Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. | Lens, led module and illumination apparatus utilizing the same |
US20110026918A1 (en) | 2009-08-03 | 2011-02-03 | Electronics And Telecommunications Research Institute | Apparatus for visible light communication indicating communication quality using rgb color mixing and method thereof |
US8494218B2 (en) | 2009-08-18 | 2013-07-23 | Industrial Technology Research Institute | Light information receiving method, unit and method for recognition of light-emitting objects |
US20110069962A1 (en) | 2009-09-18 | 2011-03-24 | Interdigital Patent Holdings, Inc. | Method and apparatus for dimming with rate control for visible light communications (vlc) |
US20110069951A1 (en) | 2009-09-19 | 2011-03-24 | Samsung Electronics Co., Ltd. | Apparatus and method for supporting mobility of a mobile terminal that performs visible light communication |
US20110105134A1 (en) | 2009-10-31 | 2011-05-05 | Samsung Electronics Co., Ltd. | Visible light communication method and apparatus |
US20110115816A1 (en) | 2009-11-16 | 2011-05-19 | Alliance For Sustainable Energy, Llc. | Augmented reality building operations tool |
US20110191237A1 (en) | 2009-11-25 | 2011-08-04 | Patrick Faith | Information Access Device and Data Transfer |
WO2011064332A1 (en) | 2009-11-27 | 2011-06-03 | Hochschule Bochum | A navigation system and method for navigation using location signals from light sources |
US20110136536A1 (en) | 2009-12-03 | 2011-06-09 | Qualcomm Incorporated | Method and apparatus for distributed processing for wireless sensors |
US20110135317A1 (en) | 2009-12-03 | 2011-06-09 | Samsung Electronics Co., Ltd. | Controlling brightness of light sources used for data transmission |
US20110137881A1 (en) | 2009-12-04 | 2011-06-09 | Tak Keung Cheng | Location-Based Searching |
US20110153201A1 (en) | 2009-12-23 | 2011-06-23 | Samsung Electronics Co., Ltd. | Indoor navigation method and system using illumination lamps |
US8379107B2 (en) | 2009-12-31 | 2013-02-19 | Lite-On Semiconductor Corp. | Flicker detection method and image sensing device utilizing the same |
US20110176803A1 (en) | 2010-01-15 | 2011-07-21 | Samsung Electronics Co., Ltd. | System and method for indoor positioning using led lighting |
US20130040380A1 (en) | 2010-01-26 | 2013-02-14 | University Of Georgia Research Foundation, Inc. | Biological optimization systems for enhancing photosynthetic efficiency and methods of use15 |
US20110199017A1 (en) | 2010-02-15 | 2011-08-18 | Osram Gesellschaft Mit Beschraenkter Haftung | Circuit and method for driving a luminous means |
US20110222858A1 (en) | 2010-03-09 | 2011-09-15 | Kddi R&D Laboratories Inc. | Optical communication apparatus and optical communication method |
US20110266959A1 (en) | 2010-04-06 | 2011-11-03 | Lutron Electronics Co., Inc. | Method of Striking a Lamp in an Electronic Dimming Ballast Circuit |
US20110299857A1 (en) | 2010-06-02 | 2011-12-08 | Sony Corporaton | Transmission device, transmission method, reception device, reception method, communication system, and communication method |
US20110298886A1 (en) | 2010-06-06 | 2011-12-08 | Apple, Inc. | Auto Exposure Techniques for Variable Lighting Conditions |
US20120133815A1 (en) | 2010-06-08 | 2012-05-31 | Koji Nakanishi | Information display apparatus, display control integrated circuit, and display control method |
US20120093241A1 (en) | 2010-10-15 | 2012-04-19 | Ikanos Communications, Inc. | Dsl alien noise reduction |
US20120126909A1 (en) | 2010-11-18 | 2012-05-24 | Mccune Jr Earl W | Duty cycle translator methods and apparatus |
US20120155889A1 (en) | 2010-12-15 | 2012-06-21 | Electronics And Telecommunications Research Institute | Method and apparatus for transmitting and receiving data using visible light communication |
WO2012093241A1 (en) | 2011-01-07 | 2012-07-12 | Toshiba Research Europe Limited | Localisation of electronic equipment |
US20120176038A1 (en) | 2011-01-10 | 2012-07-12 | Cheon Eun | Light emitting diode emitting device |
US20120252495A1 (en) | 2011-01-11 | 2012-10-04 | Qualcomm Incorporated | Positioning system using light information |
WO2012127439A1 (en) | 2011-03-22 | 2012-09-27 | Koninklijke Philips Electronics N.V. | Light detection system and method |
US20120256697A1 (en) | 2011-04-07 | 2012-10-11 | Peter Singerl | System and Method for Generating a Pulse-width Modulated Signal |
US20120275795A1 (en) | 2011-04-26 | 2012-11-01 | The Boeing Company | System and method of wireless optical communication |
WO2012165800A2 (en) | 2011-05-27 | 2012-12-06 | Samsung Electronics Co., Ltd. | Apparatus and method for identifying location information by using visible light communication and gps |
US20120328302A1 (en) | 2011-06-23 | 2012-12-27 | Casio Computer Co., Ltd. | Information transmission system, information sending device, information receiving device, information transmission method, information sending method, information receiving method and program product |
US8334898B1 (en) | 2011-07-26 | 2012-12-18 | ByteLight, Inc. | Method and system for configuring an imaging device for the reception of digital pulse recognition information |
US20130141555A1 (en) | 2011-07-26 | 2013-06-06 | Aaron Ganick | Content delivery based on a light positioning system |
US20130026940A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Self identifying modulated light source |
US20130028612A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for modulating a beacon light source in a light based positioning system |
US20130028609A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for demodulating a digital pulse recognition signal in a light based positioning system using a fourier transform |
US20130029682A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for tracking and analyzing data obtained using a light based positioning system |
US20130028475A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Light positioning system using digital pulse recognition |
US20130026945A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for modifying a beacon light source for use in a light based positioning system |
US20130026941A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Single wavelength light source for use in light based positioning system |
US20130030747A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for calibrating a light based positioning system |
US20130026942A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Device for dimming a beacon light source used in a light based positioning system |
US20130027528A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for video processing to determine digital pulse recognition tones |
US20130026224A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for determining the position of a device in a light based positioning system using locally stored maps |
US8334901B1 (en) | 2011-07-26 | 2012-12-18 | ByteLight, Inc. | Method and system for modulating a light source in a light based positioning system using a DC bias |
US8416290B2 (en) | 2011-07-26 | 2013-04-09 | ByteLight, Inc. | Method and system for digital pulse recognition demodulation |
US8994799B2 (en) | 2011-07-26 | 2015-03-31 | ByteLight, Inc. | Method and system for determining the position of a device in a light based positioning system using locally stored maps |
US8432438B2 (en) | 2011-07-26 | 2013-04-30 | ByteLight, Inc. | Device for dimming a beacon light source used in a light based positioning system |
US8436896B2 (en) | 2011-07-26 | 2013-05-07 | ByteLight, Inc. | Method and system for demodulating a digital pulse recognition signal in a light based positioning system using a Fourier transform |
US8994814B2 (en) | 2011-07-26 | 2015-03-31 | ByteLight, Inc. | Light positioning system using digital pulse recognition |
US8457502B2 (en) | 2011-07-26 | 2013-06-04 | ByteLight, Inc. | Method and system for modulating a beacon light source in a light based positioning system |
US20130141554A1 (en) | 2011-07-26 | 2013-06-06 | Aaron Ganick | Independent beacon based light position system |
US20130027576A1 (en) | 2011-07-26 | 2013-01-31 | ByteLight, Inc. | Method and system for digital pulse recognition demodulation |
US8248467B1 (en) | 2011-07-26 | 2012-08-21 | ByteLight, Inc. | Light positioning system using digital pulse recognition |
US20130208132A1 (en) | 2011-07-26 | 2013-08-15 | ByteLight, Inc. | Method and system for configuring an imaging device for the reception of digital pulse recognition information |
US8520065B2 (en) | 2011-07-26 | 2013-08-27 | ByteLight, Inc. | Method and system for video processing to determine digital pulse recognition tones |
US8964016B2 (en) | 2011-07-26 | 2015-02-24 | ByteLight, Inc. | Content delivery based on a light positioning system |
US8947513B2 (en) | 2011-07-26 | 2015-02-03 | Byelight, Inc. | Method and system for tracking and analyzing data obtained using a light based positioning system |
US20140045549A1 (en) | 2011-07-26 | 2014-02-13 | ByteLight, Inc. | Configuration and management of light positioning system using digital pulse recognition |
US20140086590A1 (en) | 2011-07-26 | 2014-03-27 | ByteLight, Inc. | Self-identifying one-way authentication method using optical signals |
US8866391B2 (en) | 2011-07-26 | 2014-10-21 | ByteLight, Inc. | Self identifying modulated light source |
EP2737779A1 (en) | 2011-07-26 | 2014-06-04 | Bytelight, Inc. | Self identifying modulater light source |
US20140139744A1 (en) | 2011-07-26 | 2014-05-22 | ByteLight, Inc. | Method and system for video processing to remove noise from a digital video sequence containing a modulated light signal |
US20130094668A1 (en) | 2011-10-13 | 2013-04-18 | Jens Kristian Poulsen | Proximity sensing for user detection and automatic volume regulation with sensor interruption override |
US20130126713A1 (en) | 2011-11-04 | 2013-05-23 | The University Court Of The University Of Edinburgh | Communication apparatus and method |
US8957951B1 (en) | 2011-12-06 | 2015-02-17 | ByteLight, Inc. | Content delivery based on a light positioning system |
US9055200B1 (en) | 2011-12-06 | 2015-06-09 | ByteLight, Inc. | Content delivery based on a light positioning system |
US9054803B1 (en) | 2011-12-06 | 2015-06-09 | ByteLight, Inc. | Content delivery based on a light positioning system |
US20130297212A1 (en) | 2012-05-03 | 2013-11-07 | David P. Ramer | Networked architecture for system of lighting devices having sensors, for intelligent applications |
US20130293877A1 (en) | 2012-05-03 | 2013-11-07 | David P. Ramer | Lighting devices with sensors for detecting one or more external conditions and networked system using such devices |
US8732031B2 (en) | 2012-06-12 | 2014-05-20 | Sensity Systems, Inc. | Lighting infrastructure and revenue model |
WO2014063150A2 (en) | 2012-10-19 | 2014-04-24 | Daniel Ryan | Self-identifying one-way authentication method using optical signals |
US20150043425A1 (en) | 2013-08-12 | 2015-02-12 | Abl Ip Holding Llc | Lighting element-centric network of networks |
Non-Patent Citations (101)
Title |
---|
Canadian Examination Report for Canadian Application No. 2,842,826, dated Apr. 19, 2018, 3 pages. |
Canadian Examination Report for Canadian Application No. 2892923, dated Apr. 25, 2017, 4 pages. |
Canadian Examination Report for Canadian Application No. 2892923, dated Jun. 8, 2016, 4 pages. |
Canadian Office Action for Canadian Application No. 2,892,923, dated Mar. 1, 2018, 6 pages. |
Davies, C. "VLC D-Light LED Networking Takes on Wifi and GPS," [Video] http://www.slashgear.com/vlc-d-light-led-networking-takes-on-wifi-and-gps-video-08170160/> Speech given Jul. 2011, Published to the Internet Aug. 8, 2011, Transcript attached, 3 pages. |
Entire patent prosecution history of U.S. Appl. No. 14/490,207, filed Sep. 18, 2014, entitled, "Self Identifying Modulated Light Source." |
Entire patent prosecution history of U.S. Appl. No. 15/054,541, filed Feb. 26, 2016, entitled, "Method and System for Configuring an Imaging Device for the Reception of Digital Pulse Recognition Information." |
Entire patent prosecution history of U.S. Appl. No. 15/136,275, filed Apr. 22, 2016, entitled, "Self-Identifying One-Way Authentication Method Using Optical Signals." |
EP Search Report for Application No. 12817835.7 dated Nov. 27, 2015 , 3 pages. |
European Communication for European Application No. 13847543.9, dated Aug. 3, 2018, 7 pages. |
European Communication for European Application No. 16184630.8, dated Jan. 7, 2019, 10 pages. |
European Communication Pursuant to Article 94(3) for European Application No. 12817835.7, dated Feb. 2, 2018, 15 pages. |
European Communication Pursuant to Article 94(3) for European Application No. 13847543.9, dated Dec. 15, 2017, 7 pages. |
European Communication Pursuant to Article 94(3) for European Application No. 16184630.8, dated Mar. 16, 2018, 6 pages. |
European Office Action for European Application No. 13847543.9, dated Jun. 8, 2017, 6 pages. |
Extended European Search Report for European Application No. 13847543.9, dated Jul. 27, 2016. |
Extended European Search Report received for European Patent Application No. 12817835.7, dated Mar. 23, 2015, 4 pgs. |
Final Office Action dated Nov. 17, 2015 issued in U.S. Appl. No. 13/718,233, 13 pages. |
Final Office Action for U.S. Appl. No. 13/526,781, dated Jul. 26, 2016, 39 pages. |
Final Office Action for U.S. Appl. No. 14/988,827, dated Dec. 19, 2017, 36 pages. |
Final Office Action for U.S. Appl. No. 14/991,344, dated Jun. 2, 2017, 29 pages. |
Final Office Action for U.S. Appl. No. 14/991,344, dated Sep. 6, 2018, 34 pages. |
Final Office Action for U.S. Appl. No. 15/007,692, dated Jan. 3, 2018, 28 pages. |
Final Office Action for U.S. Appl. No. 15/063,763, dated Feb. 7, 2019, 29 pages. |
Final Office Action for U.S. Appl. No. 15/233,302, dated Feb. 16, 2018, 25 pages. |
Gursoy, et al., "On-Off Frequency-Shift Keying for Wideband Fading Channels," EURASIP Journal on Wireless Communications and Networking, Article 98564, pp. 1-15 (2006). |
H.L. Lee, "A Photon Modeling Method For The Characterization Of Indoor Optical Wireless Communication", Progress In Electromagnetics Research, PIER 92, 2009, pp. 121-136. |
Haruyama, S., "Visible Light Communications: Recent Activities in Japan," Smart Spaces: A Smart Lighting ERC Industry-Academia Day at BU Photonics Center, Boston University (Feb. 8, 2011) (49 pages). |
Haruyama, S., "Visible Light Communications: Recent Activities in Japan," Smart Spaces: A Smart Lighting ERC Industry—Academia Day at BU Photonics Center, Boston University (Feb. 8, 2011) (49 pages). |
International Preliminary Report on Patentability received for PCT Patent Application No. PCT/US2012/048164, dated Jan. 28, 2014, 8 pages. |
International Preliminary Report on Patentability received for PCT Patent Application No. PCT/US2013/065923, dated Apr. 21, 2015, 5 pages. |
International Search Report and Written Opinion for PCT/US12/48164, dated Nov. 29, 2012, 13 pages. |
International Search Report and Written Opinion issued for PCT/US2012/048164, dated Nov. 29, 2012, 13 pgs. |
International Search Report received for PCT Patent Application No. PCT/US2013/065923, dated May 7, 2014, 4 pages. |
Khan, T.A., "Visible Light Communications Using Wavelength Division Multiplexing," Thesis for Univ. of Engineering and Technology Lahore, Dept. of Elec. Engineering, (82 pages) (2006). |
Lee, "A Photon Modeling Method For The Characterization Of Indoor Optical Wireless Communication", Progress In Electromagneics Research, PIER 92, 2009, pp. 121-136. |
Liu, H.S. and Pang, G. "Positioning Beacon System Using Digital Camera and LEDs," IEEE Trans. Vehic. Tech., vol. 52(2): 403-419 (Mar. 2003). |
Masaki Yoshino, Shinichiro Harauyama, and Masao Nakagawa; High-accuracy Positioning System using Visible LED Lights and Image Sensor, pp. 439-442, Radio and Wireless Symposium, 2008 IEEE, Date of Conference: Jan. 22-24, 2208, 4 pages. |
Matsushita et al., "ID Cam: A Smart Camera for Scene Capturing and ID Recognition", Transactions of Information Processing Society of Japan, vol. 43, No. 12, Dec. 15, 2002, pp. 3664-3674. |
Minh et al., "High-Speed Visible Light Communications Using Multiple-Resonant Equalization", IEEE Photonics Tecnology Letters, vol. 20, No. 14, Jul. 15, 2008, pp. 1243-1245. |
Non Final Office Action dated Aug. 3, 2017 for U.S. Appl. No. 15/136,275, dated Aug. 3, 2017, 25 pages. |
Non Final Office action dated Jan. 14, 2016 for U.S. Appl. No. 13/526,781 entitled "Method and System for Modifying a Beacon Light Source for Use in a Light Based Positioning System." (33 pages). |
Non Final Office Action dated Jul. 1, 2015 in U.S. Appl. No. 14/210,832, 41 pages. |
Non Final Office Action dated Jun. 11, 2015 in U.S. Appl. No. 13/718,233, 39 pages. |
Non Final Office action dated Jun. 15, 2015 in U.S. Appl. No. 14/019,376, 28 pages. |
Non Final Office Action dated Jun. 16, 2015 in U.S. Appl. No. 14/490,207, 22 pages. |
Non Final Office Action for U.S. Appl. No. 14/297,254, dated Aug. 19, 2016, 49 pages. |
Non Final Office Action for U.S. Appl. No. 14/943,485, dated Jan. 11, 2017, 28pages. |
Non Final Office Action for U.S. Appl. No. 14/957,146, dated Oct. 18, 2016, 24pages. |
Non Final Office Action for U.S. Appl. No. 14/988,827, dated Jul. 5, 2017, 43 pages. |
Non Final Office Action for U.S. Appl. No. 14/991,344, dated Mar. 2, 2018, 32 pages. |
Non Final Office Action for U.S. Appl. No. 14/991,344, dated Nov. 30, 2016, 31 pages. |
Non Final Office Action for U.S. Appl. No. 15/007,675, dated Jul. 7, 2017, 46 pages. |
Non Final Office Action for U.S. Appl. No. 15/007,692, dated Jul. 31, 2017, 21 pages. |
Non Final Office Action for U.S. Appl. No. 15/045,519, dated Jul. 26, 2017, 32 pages. |
Non Final Office Action for U.S. Appl. No. 15/049,869, dated Nov. 3, 2016, 24pages. |
Non Final Office Action for U.S. Appl. No. 15/058,570, dated Aug. 31, 2018, 62 pages. |
Non Final Office Action for U.S. Appl. No. 15/063,763, dated Aug. 10, 2018, 72 pages. |
Non Final Office Action for U.S. Appl. No. 15/093,120, dated Apr. 17, 2017, 26pages. |
Non Final Office Action for U.S. Appl. No. 15/095,457, dated Aug. 24, 2017, 29 pages. |
Non Final Office Action for U.S. Appl. No. 15/233,302, dated Jul. 24, 2017, 11 pages. |
Non Final Office Action for U.S. Appl. No. 15/681,618, dated Jul. 24, 2018, 42 pages. |
Non Final Office Action for U.S. Appl. No. 15/958,443, dated Oct. 29, 2018, 29 pages. |
Notice of Allowance dated Apr. 13, 2016 in U.S. Appl. No. 14/210,832, filed Mar. 14, 2014 entitled "Location-Based Mobile Services and Applications." (14 pages). |
Notice of Allowance dated Dec. 3, 2015 for U.S. Appl. No. 14/490,207 entitled "Self Identifying Modulated Light Source." (16 pages). |
Notice of Allowance dated Jan. 12, 2016 for U.S. Appl. No. 14/163,772 entitled "Method and System for Video Processing to Remove Noise From a Digital Video Sequence Containing a Modulated Light Signal." (15 pages). |
Notice of Allowance dated Jun. 12, 2015 in U.S. Appl. No. 13/369,144, 12 pages. |
Notice of Allowance dated May 10, 2016 in U.S. Appl. No. 14/163,772, filed Jan. 24, 2014, entitled "Method and System for Video Processing to Remove Noise From a Digital Video Sequence Containing a Modulated Light Signal." (10 pages). |
Notice of Allowance dated May 3, 2016 for U.S. Appl. No. 14/058,678 entitled "Self-Identifying One-Way Authentication Method Using Optical Signals." (40 pages). |
Notice of Allowance dated Oct. 9, 2015 in U.S. Appl. No. 13/369,144, filed Feb. 8, 2012, entitled "Independent Beacon Based Light Position System." (9 pages). |
Notice of Allowance for U.S. Appl No. 15/058,570, dated Feb. 6, 2019, 16 pages. |
Notice of Allowance for U.S. Appl. No. 13/526,781, dated Nov. 30, 2016, 15 pages. |
Notice of Allowance for U.S. Appl. No. 13/718,233, dated Mar. 16, 2016, entitled "Recognition Information." (17 pages). |
Notice of Allowance for U.S. Appl. No. 14/019,376, dated Oct. 27, 2015, 12 pages. |
Notice of Allowance for U.S. Appl. No. 14/297,254, dated Jan. 5, 2017, 13 pages. |
Notice of Allowance for U.S. Appl. No. 14/943,485, dated Jun. 5, 2017, 11 pages. |
Notice of Allowance for U.S. Appl. No. 14/957,146, dated Jan. 11, 2017, 9pages. |
Notice of Allowance for U.S. Appl. No. 14/988,827, dated Apr. 16, 2018, 20 pages. |
Notice of Allowance for U.S. Appl. No. 14/991,344, dated Feb. 6, 2019, 20 pages. |
Notice of Allowance for U.S. Appl. No. 15/007,614, dated Jul. 28, 2017, 11 pages. |
Notice of Allowance for U.S. Appl. No. 15/007,675, dated Dec. 18, 2017, 14 pages. |
Notice of Allowance for U.S. Appl. No. 15/007,692, dated Apr. 20, 2018, 18 pages. |
Notice of Allowance for U.S. Appl. No. 15/045,519, dated Oct. 31, 2017, 13 pages. |
Notice of Allowance for U.S. Appl. No. 15/049,869, dated Mar. 1, 2017, 12pages. |
Notice of Allowance for U.S. Appl. No. 15/054,541, dated Jul. 5, 2017, 28 pages. |
Notice of Allowance for U.S. Appl. No. 15/054,726, dated Aug. 1, 2017, 11 pages. |
Notice of Allowance for U.S. Appl. No. 15/093,120, dated Sep. 22, 2017, 13 pages. |
Notice of Allowance for U.S. Appl. No. 15/095,457, dated Nov. 22, 2017, 11 pages. |
Notice of Allowance for U.S. Appl. No. 15/136,275, dated Jan. 10, 2018, 15 pages. |
Notice of Allowance for U.S. Appl. No. 15/681,618, dated Nov. 7, 2018, 13 pages. |
Notice of Allowance for U.S. Appl. No. 15/958,443, dated Jan. 18, 2019, 12 pages. |
Osborne, D., "New LED Ceiling Lights transmit data using visible light," http://www.geek.com/articles/chips/new-led-ceiling-lights-transmit-data-using-visible-light-20110117/ (Jan. 17, 2011) (2 pages). |
Partial Supplementary European Search Report dated Apr. 7, 2016 for European Application No. 13847543.9, 7 pages. |
PCT International Patent Application No. PCT/US2014/067390, International Search Report and Written Opinion dated Mar. 12, 2015, 13 pages. |
Pohlmann, "Visible Light Communication," Seminar Kommunikationsstandards in Medizintechnik, Jun. 29, 2010 (14 pages). |
Steven P. Nicklin, Robin D. Fisher, and Richard H. Middleton; Rolling Shutter Image Compensation; pp. 402-409; RoboCup 2006: Robot Soccer World Cup X, Lecture Notes in Computer Science, vol. 4434, 2007, 8 pages. |
Tanaka et al. "New Position Detection Method Using Image Sensor and Visible Light LEDs," Second International Conference on Machine Vision, 2009, pp. 150-153. |
Tjan, B.S., et al., "Digital sign system for indoor wayfinding for the visually impaired" Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR)-Workshops, 3, 30A. San Diego, CA (8 pages), Jun. 25, 2005. |
Tjan, B.S., et al., "Digital sign system for indoor wayfinding for the visually impaired" Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR)—Workshops, 3, 30A. San Diego, CA (8 pages), Jun. 25, 2005. |
Visible Light Communication (VLC) Systems; <http://bemri.org/visible-light-communication.html> (Retrieved Mar. 10, 2012)-7 pages. |
Visible Light Communication (VLC) Systems; <http://bemri.org/visible-light-communication.html> (Retrieved Mar. 10, 2012)—7 pages. |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11381786B2 (en) * | 2018-11-23 | 2022-07-05 | Curtis Ray Robinson, JR. | Systems and methods for capturing images and video |
Also Published As
Publication number | Publication date |
---|---|
US20160241338A1 (en) | 2016-08-18 |
US20190222315A1 (en) | 2019-07-18 |
US9973273B2 (en) | 2018-05-15 |
US9444547B2 (en) | 2016-09-13 |
US10484092B2 (en) | 2019-11-19 |
US20180234182A1 (en) | 2018-08-16 |
US20140086590A1 (en) | 2014-03-27 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10484092B2 (en) | Modulating a light source in a light based positioning system with applied DC bias | |
US9918013B2 (en) | Method and apparatus for switching between cameras in a mobile device to receive a light signal | |
US10237489B2 (en) | Method and system for configuring an imaging device for the reception of digital pulse recognition information | |
US10334683B2 (en) | Method and system for modifying a beacon light source for use in a light based positioning system | |
US9418115B2 (en) | Location-based mobile services and applications | |
US8334901B1 (en) | Method and system for modulating a light source in a light based positioning system using a DC bias | |
US8457502B2 (en) | Method and system for modulating a beacon light source in a light based positioning system | |
US8436896B2 (en) | Method and system for demodulating a digital pulse recognition signal in a light based positioning system using a Fourier transform | |
US8432438B2 (en) | Device for dimming a beacon light source used in a light based positioning system | |
CA2892923C (en) | Self-identifying one-way authentication method using optical signals | |
US8520065B2 (en) | Method and system for video processing to determine digital pulse recognition tones |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
AS | Assignment |
Owner name: BYTELIGHT, INC., MASSACHUSETTS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GANICK, AARON;RYAN, DANIEL;SIGNING DATES FROM 20140815 TO 20140901;REEL/FRAME:045534/0173 |
|
AS | Assignment |
Owner name: ABL IP HOLDING LLC, GEORGIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BYTELIGHT, INC.;REEL/FRAME:045552/0344 Effective date: 20150415 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 4 |